Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies (2020)

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F-1 A P P E N D I X F Regionally Specific Roadside Milkweed Recognition Fact Sheets Milkweeds of Arkansas, Louisiana, & Mississippi Milkweeds of Arizona & New Mexico Milkweeds of California Milkweeds of Colorado Milkweeds of Florida Milkweeds of the Great Lakes Milkweeds of Iowa & Minnesota Milkweeds of Idaho, Oregon, & Washington Milkweeds of Kansas & Missouri Milkweeds of the Mid-Atlantic Milkweeds of Montana & Wyoming Milkweeds of Nebraska & The Dakotas Milkweeds of Nevada & Utah Milkweeds of the Northeast Milkweeds of Oklahoma & Texas Milkweeds of the Southeast

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-3 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Prairies, old fields, open woodlands. SOILS: Sandy, loamy, rocky; dry–mesic. BLOOM: May–Aug; orange to red or yellow. Redring milkweed (A. variegata) PLANT: Upright, unbranched stem; purplish-green; usually smooth. LEAVES: Opposite; oval-shaped; usually smooth. HABITAT: Savannas, rocky woodlands and edges, banks of streams; prefers some shade. SOILS: Sandy, rocky, loam to clay-loamy; dry–mesic. BLOOM: May–Jul; white to light green, with red or purple ring. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or short hairs. HABITAT: Prairies, open woods, fields, flood plains, disturbed areas. SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: May–Oct; white to green. Green comet milkweed (A. viridiflora) PLANT: Multiple unbranched spreading to upright stems; with short hairs. LEAVES: Opposite; either lance- or oval-shaped; with edges folded upward or wavy. HABITAT: Prairies, old fields, dunes, open woodlands. SOILS: Rocky or sandy, but tolerates loamy; dry–dry-mesic. BLOOM: Jun–Aug; light green to yellowish green. The most common milkweeds in roadsides in Arkansas, Louisiana & Mississippi (in alphabetical order): MILKWEEDS OF ARKANSAS, LOUISIANA & MISSISSIPPI

F-4 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Arkansas, Louisiana, and/or Mississippi: Asclepias incarnata, A. lanceolata, A. longifolia, A. michauxii, A. obovata, A. oenotheroides, A. quadrifolia, A. rubra, A. stenophylla, A. syriaca. Green milkweed (A. hirtella) PLANT: Unbranched, upright stems; 3’ max. LEAVES: Alternate; long and narrow to lance-shaped; short hairs. SOILS/HABITAT: Sandy to rocky or clayey; dry–moist; prairies, meadows, open woods, sometimes marshes. BLOOM: Jun– Sep; green with purple or cream. Purple milkweed (A. purpurascens) PLANT: Upright, unbranched, stout stems; smooth; 6’ max. LEAVES: Opposite; oval-shaped; smooth above with fine hairs below. SOILS/ HABITAT: Loamy to clayey; mesic; prairies, meadows, woodland edges, savannas. BLOOM: May–Jul; dark rose to purple. Aquatic milkweed (A. perennis) PLANT: Multiple upright stems branching from base; dark green and hairless; 2’ max. LEAVES: Opposite; lance- to oval-shaped; often green all winter. SOILS/HABITAT: Wetland soils; ditches, streams, swamps. BLOOM: May– Nov; white flowers (pink-tipped when in bud). Clasping milkweed (A. amplexicaulis) PLANT: Unbranched, upright stems; smooth; 3’ max. LEAVES: Opposite; oval-shaped; wavy margins; base of leaves clasp stem. SOILS/HABITAT: Sandy, rocky; dry; sandhills, grasslands, savannahs. BLOOM: May–Jul; green with pink or purple. Green antelopehorn (A. viridis) PLANT: Multiple unbranched, upright stems; usually smooth. LEAVES: Alternate; lance- to oval-shaped with wavy margins. HABITAT: Upland grasslands, disturbed areas. SOILS: Sandy, rocky, clayey; dry. BLOOM: Mar– Sep; green with touches of purple. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Ray Moranz, Sarah Hamilton Buxton, and Stephanie Frischie (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Philip Barbour, USDA–NRCS. Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Mary Keim / flickr (A. perennis); Krista Lundgren, USFWS / flickr (A. viridiflora); Jerry Oldenettel / flickr (A. verticillata, A. viridis); Tom Potterfield / flickr (A. purpurascens); Karan A. Rawlins, University of Georgia / Bugwood.org (A. variegata); Paul Rothrock / SEINet (A. amplexicaulis, A. hirtella); Scott Seigfreid (A. tuberosa). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-016_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-5 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in Arizona & New Mexico (in alphabetical order): Spider milkweed (A. asperula ssp. asperula) PLANT: Multiple spreading stems, unbranched to few branches; usually smooth. LEAVES: Alternate; lance-shaped; usually folded lengthwise. HABITAT: Upland grasslands, disturbed areas. SOILS: Sandy to clayey, gravelly and rocky limestone; dry. BLOOM: Apr–Jun (may have a second later bloom with rains); light green with touches of purple. Desert milkweed (A. erosa) PLANT: Upright, unbranched to branched stout stems; with fine hairs; grows in clumps. LEAVES: Opposite; oval- to lance-shaped; smooth or with fine hairs. HABITAT: Washes, gulches, canyons, disturbed areas in deserts, creosote bush and sagebrush communities. SOILS: Sandy; dry. BLOOM: Apr–Oct; yellowish or cream; flower buds hairy. Rush milkweed (A. subulata) PLANT: Shrub growth form with multiple unbranched to branched stems from the base; smooth; mostly leafless. LEAVES: Opposite; narrow to linear; emerging after rains. HABITAT: Slopes, mesas, plains, desert washes. SOILS: Sandy, rocky; dry. BLOOM: Apr–Oct; whitish green with yellow. Showy milkweed (A. speciosa) PLANT: Stout, upright, unbranched stems; hairy. LEAVES: Opposite; broad and oval-shaped; hairy. HABITAT: Grasslands, fallow fields, disturbed areas, banks of irrigation ditches, rivers, ponds. SOILS: Sandy to loamy; dry–moist. BLOOM: May–Aug; pink and cream or white; flowers are the largest of American species. MILKWEEDS OF ARIZONA & NEW MEXICO

F-6 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Arizona and/or New Mexico: Asclepias albicans, A. angustifolia, A. arenaria, A. cryptoceras, A. cutleri, A. emoryi, A. glaucescens, A. hallii, A. hypoleuca, A. incarnata, A. involucrata, A. lemmonii, A. macrosperma, A. macrotis, A. nummularia, A. nyctaginifolia, A. oenotheroides, A. pumila, A. quinquedentata, A. rusbyi, A. ruthiae, A. scaposa, A. tuberosa, A. uncialis, A. verticillata, A. viridiflora, A. welshii. Bract milkweed (A. brachystephana) PLANT: Upright, branched stems; with short woolly hairs, smoothes with age; 1’ max. LEAVES: Opposite; lance- shaped to narrow; edges folded up; woolly above, smooth below. SOILS/HABITAT: Sandy, rocky; dry; desert mountains, grasslands, mesas, disturbed areas. BLOOM: Apr–Sep; dull purple. Engelmann’s milkweed (A. engelmanniana) PLANT: One to a few upright, stout stems; typically unbranched; smooth; 3’ max. LEAVES: Irregularly alternate; linear; smooth. SOILS/ HABITAT: Sandy, rocky; dry; desert mountains and dry plains, grasslands, mesas, disturbed areas. BLOOM: Jun–Sep; green with yellow. Broadleaf milkweed (A. latifolia) PLANT: Upright, unbranched, stout stems; woolly when young to smooth with age; 2’ max. LEAVES: Opposite; numerous, broadly oval; woolly when young to smooth with age. SOILS/ HABITAT: Sandy, rocky; dry; disturbed areas, grasslands. BLOOM: May–Aug; white to pale green. Pineneedle milkweed (A. linaria) PLANT: Shrub-like; upright stems with multiple branches; with fine hairs; 5’ max. LEAVES: Alternate or appearing whorled; narrow, needle-like. SOILS/ HABITAT: Rocky; dry; slopes, mesas. BLOOM: Feb– Nov; white to greenish with pink or purple. Horsetail milkweed (A. subverticillata) PLANT: Upright, branched or unbranched stems; smooth or with fine hairs. LEAVES: Whorled; narrow to linear; smooth. HABITAT: Disturbed areas, ditches, streams. SOILS: Sandy; moist. BLOOM: Jul–Aug; yellow to cream or purple. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across both states and are found in roadsides. Less common species might not occur in both states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https:// plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Stephanie McKnight and Jennifer Hopwood (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Gail Morris (Southwest Monarch Study). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Patrick Alexander / SEINet (A. subulata, A. brachystephana); Frankie Coburn / SEINet (A. linaria); Max Licher / SEINet (A. subverticillata, A. engelmanniana, A. latifolia); Xerces Society / Stephanie McKnight (A. erosa, A. speciosa); Andrey Zharkikh / flickr (A. a. ssp. asperula). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-017_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-7 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an on roadsides in your region. (Continued on next page.) Desert milkweed (A. erosa) PLANT: grows in clumps. LEAVES: Opposite; oval- to lance-shaped; smooth or with HABITAT: Washes, gulches, canyons, disturbed areas in deserts, creosote bush and sagebrush communities. SOILS: Sandy; dry. BLOOM: Heartleaf milkweed (A. cordifolia) PLANT: Spreading to upright stout stems; mostly hairless. LEAVES: Opposite; heart- to lance-shaped; with waxy coating. HABITAT: Slopes and hillsides in foothill woodland, chaparral, and evergreen forest. SOILS: Rocky, gravelly; dry. BLOOM: Apr–Jul; red-purple to violet with pink or white tinges. Narrowleaf milkweed (A. fascicularis) PLANT: Thin, upright branched stems; smooth. LEAVES: Opposite to whorled; narrow to lance-shaped; pointed and folded lengthwise; mostly smooth. HABITAT: Valley grasslands, wetland-riparian areas, open woodlands, chaparral, sagebrush, disturbed areas, banks of streams and SOILS: Sandy to clayey; dry–moist. BLOOM: May–Oct; dusky pink to rose with touches of white. The most common milkweeds in roadsides in California (in alphabetical order): Woollypod milkweed (A. eriocarpa) PLANT: Upright, usually unbranched stems; densely hairy but may be less so with age. LEAVES: Opposite; lance- to oval-shaped; may be wavy at edges; hairy but may be less so with age. HABITAT: Valley grassland, chaparral, foothill woodland, stream banks, disturbed areas. SOILS: Rocky; dry. BLOOM: May–Oct; cream or yellow with white or tinges of purple or pink. KEY MAY BE MORE TOLERANT OF MOWING MILKWEEDS OF CALIFORNIA Upright, unbranched to branched stout stems; with fine hairs; Apr—Oct; yellowish or cream, flower buds hairy. fine hairs. irrigation ditches, fallow fields. essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found

F-8 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in California: Asclepias asperula, A. cryptoceras, A. fruticosa, A. latifolia, A. linaria, A. nyctaginifolia, A. solanoana. Showy milkweed (A. speciosa) PLANT: Stout, upright, unbranched stems; hairy. LEAVES: Opposite; broad and oval-shaped; hairy. HABITAT: Grasslands, fallow fields, disturbed areas, foothill woodlands, wetland-riparian areas, banks of streams, irrigation ditches, rivers, and ponds. SOILS: Sandy to loamy; dry–moist. BLOOM: May– Aug; pink and cream or white; flowers are the largest of American species. Whitestem milkweed (A. albicans) PLANT: Shrub growth form with wand-like stems branching at tip; smooth and waxy; 10’ max. LEAVES: Opposite or in whorls of three; narrow to linear; shed during drought. SOILS/HABITAT: Rocky; dry; deserts, creosote bush scrub. BLOOM: Mar–Apr; yellow to white. California milkweed (A. californica) PLANT: Multiple spreading to upright stems; grow in clumps; very woolly; 3’ max. LEAVES: Opposite; oval-shaped; densely hairy. SOILS/ HABITAT: Sand to clay; dry; valley grasslands, yellow pine and pinyon-juniper woods, chaparral. BLOOM: Apr–Jul; pink to purple; buds hairy; flowers nodding. Rush milkweed (A. subulata) PLANT: Shrub growth form; multiple unbranched to branched stems from the base; smooth; mostly leafless; 5’ max. LEAVES: Opposite; narrow to linear; emerging after rains. SOILS/HABITAT: Sandy, rocky; dry; slopes, mesas, plains, desert washes. BLOOM: Apr–Oct; whitish green with yellow. Woolly milkweed (A. vestita) PLANT: Stout, upright stems clustered at the base; densely hairy; 2’ max. LEAVES: Opposite; oval- to lance-shaped; densely hairy. SOILS/ HABITAT: Sandy; dry; valley grassland, chaparral, foothill woodland, hillsides, canyons. BLOOM: Apr–Jul; yellow or pale green with white. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the state and are found in roadsides. Less common species might have a limited distribution across the state or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in the state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Stephanie McKnight, Jennifer Hopwood, Jessa Kay Cruz, and Angela Laws (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Frankie Coburn / SEINet (A. albicans); Professor Stephen Lynch (A. vestita); Xerces Society / Brianna Borders (A. subulata); Xerces Society / Stephanie McKnight (A. cordifolia, A eriocarpa, A. erosa, A. fascicularis, A. speciosa); Jordan Zylstra / Calphotos (A. californica). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-018_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-9 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in Colorado (in alphabetical order): Spider milkweed (A. asperula ssp. asperula) PLANT: Multiple spreading stems, unbranched to few branches; usually smooth. LEAVES: Alternate; lance-shaped; usually folded lengthwise. HABITAT: Prairie, disturbed areas. SOILS: Sandy, gravelly, clayey, rocky limestone; dry. BLOOM: Apr–Jun; light green with touches of purple. Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Grasslands and ditches, edges of ponds, lakes, streams. SOILS: Silty to loamy or clayey; wet–moist, tolerates some mesic. BLOOM: Jun–Sep; pink, light purple. Plains milkweed (A. pumila) PLANT: Upright, unbranched or branched stems; with fine hairs. LEAVES: Alternate, may appear whorled; thin and narrow; dense on stems (bottlebrush appearance). HABITAT: Prairies, plains, low hills. SOILS: Rocky, sandy; dry. BLOOM: Jun–Aug; white to greenish white. Showy milkweed (A. speciosa) PLANT: Stout upright, unbranched stems; hairy. LEAVES: Opposite; oval- shaped; hairy. HABITAT: Grasslands, old fields, disturbed areas, woodlands, wetlands, edges of rivers, ponds, and irrigation ditches. SOILS: Sandy to loamy; dry–moist. BLOOM: May–Aug; pink and cream or white; flowers are the largest of American species. MILKWEEDS OF COLORADO

F-10 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Colorado: Asclepias arenaria, A. cryptoceras, A. engelmanniana, A. involucrata, A. latifolia, A. macrotis, A. oenotheroides, A. rusbyi, A. uncialis. Broadleaf milkweed (A. latifolia) PLANT: Upright, unbranched, stout stems; woolly when young to smooth with age; 2’ max. LEAVES: Opposite; numerous, broadly oval; woolly when young to smooth with age. SOILS/ HABITAT: Sandy, rocky; dry; prairie, dry grasslands, slopes. BLOOM: May–Aug; white to pale green. Green comet milkweed (A. viridiflora) PLANT: Unbranched stems, spreading to upright; with short hairs; 3’ max. LEAVES: Opposite; lance-shaped; with margins folded upward or wavy; with short hairs. SOILS/HABITAT: Sandy to loamy or rocky; dry–dry-mesic; prairies, old fields, dunes, forests. BLOOM: Jun–Aug; light green to yellowish green. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems, with short hairs; lacks milky sap, 3’ max. LEAVES: Alternate; lance-shaped; hairy underneath. SOILS/HABITAT: Sandy, loamy, rocky; dry; prairies, old fields, open woods. BLOOM: May–Sep; orange to red or yellow. Hall’s milkweed (A. hallii) PLANT: Upright, unbranched stem or branched at base; hairy; 2’ max. LEAVES: Alternate to opposite; narrow oval-shaped; hairy. SOILS/ HABITAT: Sandy, gravelly; dry; grasslands, wash- bottoms, sagebrush, woodlands. BLOOM: Jun– Aug; purple, pink, cream or white with green. Horsetail milkweed (A. subverticillata) PLANT: Upright, branched or unbranched stems; smooth or with fine hairs. LEAVES: Whorled; narrow to linear; smooth. HABITAT: Ditches, stream edges, disturbed areas. SOILS: Sandy; moist. BLOOM: May–Aug; yellow to cream or purple tinges. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the state and are found in roadsides. Less common species might have a limited distribution across the state or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in the state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Stephanie McKnight and Jennifer Hopwood (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Frankie Coburn / SEINet (A. hallii); Max Licher / SEINet (A. subverticillata, A. latifolia); Krista Lundgren, USFWS / flickr (A. viridiflora); Tom Potterfield / flickr (A. incarnata); Scott Seigfreid (A. tuberosa); Xerces Society / Stephanie McKnight (A. speciosa); Xerces Society / Ray Moranz (A. pumilla); Andrey Zharkikh / flickr (A. a. ssp. asperula). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-019_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-11 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) Pinewoods milkweed (A. humistrata) PLANT: One to multiple sprawling stems; usually smooth. LEAVES: Opposite; oval-shaped; bases that clasp stem; purple veins; usually smooth. HABITAT: Pastures, open woods, sandhills, scrubland. SOILS: Sandy; dry. BLOOM: Mar–Jun; pink to white flowers. Fewflower milkweed (A. lanceolata) PLANT: Slender unbranched stems; smooth; with few leaves or flowers. LEAVES: Opposite; lance-shaped or narrow; smooth. HABITAT: Moist grasslands and ditches, edges of ponds, lakes, streams. SOILS: Sandy or loamy; moist; ditches, marshes, wet pine savannas, wet prairies. BLOOM: May - Aug; red and orange. Aquatic milkweed (A. perennis) PLANT: One to six upright stems branching from base; dark green and hairless. LEAVES: Opposite; lance- to oval-shaped; often green all winter. HABITAT: Wet areas, ditches, streams, swamps. SOILS: Wetland soils. BLOOM: May–Nov; white flowers (with pink when in bud). Tuba milkweed (A. tomentosa) PLANT: One or two upright, unbranched stems. LEAVES: Opposite; elliptic; with wavy margins and velvet-like hairs. HABITAT: Sand dunes, pine sandhills. SOILS: Very well-drained sands. BLOOM: May–Jun; pale yellowish green. The most common milkweeds in roadsides in Florida (in alphabetical order): MILKWEEDS OF FLORIDA

F-12 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Florida: Asclepias cinerea, A. connivens, A. curtissii, A. feayi, A. michauxii, A. obovata, A. pedicillata, A. rubra, A. variegata, A. viridiflora, A. viridis, A. viridula. NOTE: Tropical milkweed (A. curassavica) is non-native species frequently sold in Florida nurseries that can escape and invade native ecosystems, particularly south of Orlando. Monarch caterpillars feed on this plant, but it has been implicated in higher rates of diseased monarchs. Longleaf milkweed (A. longifolia) PLANT: Upright, unbranched slender stem; with few hairs; 3’ max. LEAVES: Alternate; narrow and lance-shaped; with few hairs. SOILS/HABITAT: Sandy to loamy or loam-clay; wet; pinelands, savannas, swamps. BLOOM: Jun– Sep; white and purple with green. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; 3’ max. LEAVES: Whorled; narrow to needle-like; smooth or with short hairs. SOILS/ HABITAT: Sandy, rocky, clayey; dry–mesic; grasslands, open woods, fields, flood plains. BLOOM: May–Oct (year-round in S. FL); white to green. Swamp milkweed (A. incarnata) PLANT: Multiple, upright branched stems; smooth; 6’ max. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. SOILS/ HABITAT: Silty to loamy or clayey; wet–moist; moist grasslands and pond edges. BLOOM: Jun– Sep; pink or pink/purple. Clasping milkweed (A. amplexicaulis) PLANT: Unbranched, upright stems; smooth; 3’ max. LEAVES: Opposite; oval-shaped; wavy margins; base of leaves clasp stem. SOILS/HABITAT: Sandy; dry; sandhills, grasslands, savannahs. BLOOM: May–Jul; pink or purple with green or cream. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the state and are found in roadsides. Less common species might have a limited distribution across the state or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in the state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Sandhills, scrub, old fields. SOILS: Sandy, loamy, rocky; dry–mesic. BLOOM: May–Aug; orange to red or yellow. ACKNOWLEDGMENTS: Written by Ray Moranz, Jennifer Hopwood, Nancy Lee Adamson, Stephanie Frischie and (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Scott Davis (USFWS), Jaret Daniels (University of Florida), and Mark Garland (NRCS). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Patrick Coin / flickr (A humistrata); Eleanor Dietrich / flickr (A. lanceolata [right], A. tomentosa, A. verticillata); Jerry Oldenettel / flickr (A. verticillata); Jim Fowler (A. longifolia, A. lanceolata [left]); Mary Keim / flickr (A. perennis); Tom Potterfield / flickr (A. incarnata); Paul Rothrock / SEINet (A. amplexicaulis); Scott Seigfreid (A. tuberosa). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-020_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-13 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in the Great Lakes Region (in alphabetical order): Green milkweed (A. hirtella) PLANT: Upright, unbranched stems. LEAVES: Alternate; long and narrow; pointed at tips; with short hairs. HABITAT: Prairies, meadows, open woods, disturbed areas, railways. SOILS: Sandy, rocky to clay; dry–wet. BLOOM: Jun– Aug; green with purple or cream. Swamp milkweed (A. incarnata) PLANT: One to many upright, branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Moist prairies, marshes, ditches, edges of ponds, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jun–Aug; pink or light purple. Common milkweed (A. syriaca) PLANT: One to many stout, upright, unbranched stems; usually with short dense hairs. LEAVES: Opposite; oval-shaped; hairy underneath. HABITAT: Prairies, old fields, railways, open woods, flood plains, disturbed areas. SOILS: Sandy to loamy, rocky or clayey; dry–wet. BLOOM: May–Aug; light purple or pink. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Prairies, old fields, open woods. SOILS: Sandy, loamy, rocky; dry–mesic. BLOOM: May–Aug; orange to red or yellow. MILKWEEDS OF THE GREAT LAKES MICHIGAN, OHIO, ILLINOIS, INDIANA & WISCONSIN

F-14 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in the Great Lakes region: Asclepias exaltata, A. lanuginosa, A. quadrifolia, A. ovalifolia, A. speciosa, A. stenophylla, A. variegata. Purple milkweed (A. purpurascens) PLANT: Upright, unbranched, stout stems; smooth; 6’ max. LEAVES: Opposite; oval-shaped; smooth above with fine hairs below. SOILS/ HABITAT: Loamy to clayey; mesic; prairies, meadows, woodland edges, savannas. BLOOM: May–Jul; dark rose to purple. Green comet milkweed (A. viridiflora) PLANT: Multiple unbranched, spreading or upright stems; with short hairs; 3’ max. LEAVES: Opposite; lance- or oval-shaped, edges folded upward or wavy. SOILS/HABITAT: Sandy, rocky; dry; prairies, old fields, dunes, open woods. BLOOM: Jun–Jul; light to yellowish green. Prairie milkweed (A. sullivantii) PLANT: Upright, unbranched, stout stems; smooth; 4’ max. LEAVES: Opposite; lance- to oval-shaped; very smooth. SOILS/HABITAT: Sandy clay or loamy; mesic–moist; prairies, wet meadows. BLOOM: Jun–Aug; pink with light green or purple. Clasping milkweed (A. amplexicaulis) PLANT: Upright, unbranched, stems; smooth; 3’ max. LEAVES: Opposite; oval-shaped; wavy margins; base of leaves clasp stem. SOILS/HABITAT: Sandy; dry; grasslands, savannas, woodland edges. BLOOM: Apr–Jun; pink or green with cream, sometimes purple. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or with short hairs. HABITAT: Prairies, open woods, fields, flood plains, glades, railways, disturbed areas. SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: May–Sep; white to green. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Stephanie Frischie, and Karin Jokela (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Dan Zay (Michigan NRCS). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Jim Fowler (A. syriaca); Krista Lundgren, USFWS / flickr (A. viridiflora); Joshua Mayer / flickr (A. hirtella); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata, A. purpurascens); Paul Rothrock / SEINet (A. amplexicaulis); Scott Seigfreid (A. tuberosa); Xerces Society / Ray Moranz (A. sullivantii). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-021_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-15 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. (Continued on next page.) The most common milkweeds in roadsides in Iowa & Minnesota (in alphabetical order): Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Moist prairies, marshes, ditches, edges of ponds, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jul–Aug; light to dark pink or rose purple. Common milkweed (A. syriaca) PLANT: One to many stout, upright, unbranched stems; usually with short dense hairs. LEAVES: Opposite; oval-shaped; hairy underneath. HABITAT: Prairies, old fields, railways, open woods, flood plains, disturbed areas. SOILS: Sandy to loamy, clayey or rocky; dry–wet. BLOOM: Jun–Aug; pink. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Prairies, old fields, open woods. SOILS: Sandy, loamy, rocky; dry–mesic. BLOOM: Jun–Aug; orange to red or yellow. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or with short hairs. HABITAT: Prairies, open woods, fields, flood plains, railways. SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: Jul–Sep; white to green. KEY MAY BE MORE TOLERANT OF MOWING MILKWEEDS OF IOWA & MINNESOTA

F-16 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Iowa and/or Minnesota: Asclepias amplexicaulis, A. engelmanniana, A exaltata, A. lanuginosa, A. purpurascens, A. quadrifolia, A. stenophylla. Oval-leaf milkweed (A. ovalifolia) PLANT: Upright, unbranched stems; with fine hairs; 2’ max. LEAVES: Opposite; lance-shaped to oval-shaped; fine hairs underneath. SOILS/HABITAT: Sandy, silty, loamy; dry; prairies, open woods. BLOOM: Jun–Jul; cream or white with pink or yellow. Prairie milkweed (A. sullivantii) PLANT: Stout, upright, unbranched stems; smooth; 4’ max. LEAVES: Opposite; lance- to oval-shaped; very smooth. SOILS/HABITAT: Sandy, clayey, or loamy; mesic–moist; prairies, wet meadows. BLOOM: Jun–Aug; pink with light green or purple. Showy milkweed (A. speciosa) PLANT: Stout upright, unbranched stems; hairy; 5’ max. LEAVES: Opposite; oval-shaped; hairy. SOILS/HABITAT: Sandy to loam; dry–moist; prairies, old fields, edges of rivers, ponds, disturbed areas. BLOOM: Jun–Aug; pink and cream or white; flowers are the largest of American species. Green milkweed (A. hirtella) PLANT: Upright, unbranched stems; 3’ max. LEAVES: Alternate; long and narrow to lance-shaped; with short hairs. SOILS/HABITAT: Sandy to rocky or clayey; prairies, open woods, disturbed areas. BLOOM: Jul–Aug; green with purple or cream. Green comet milkweed (A. viridiflora) PLANT: Multiple unbranched spreading to upright stems; with short hairs. LEAVES: Opposite; either lance-shaped or oval-shaped; with edges folded upward or wavy. HABITAT: Prairies, old fields, dunes, openings in forests. SOILS: Rocky, sandy; dry–dry-mesic. BLOOM: Jun–Jul; light green to yellowish green. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across both states and are found in roadsides. Less common species might not occur in both states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https:// plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Stephanie Frischie, Sarah Foltz Jordan, Karin Jokela, and Sarah Nizzi (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Alison Cariveau (Monarch Joint Venture). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Jim Fowler (A. syriaca); Krista Lundgren, USFWS / flickr (A. viridiflora); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata); Paul Rothrock / SEINet (A. hirtella); Xerces Society / Stephanie McKnight (A. speciosa); Xerces Society / Ray Moranz (A. sullivantii); Scott Seigfreid (A. tuberosa). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-022_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-17 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. (Continued on next page.) The most common milkweeds in roadsides in Idaho, Oregon & Washington (in alphabetical order): Heartleaf milkweed (A. cordifolia) PLANT: Spreading to upright stout stems; mostly hairless. LEAVES: Opposite heart- to lance-shaped; with waxy coating. HABITAT: Slopes and hillsides in woodlands, shrub steppe, chaparral, and evergreen forest (SW Oregon only). SOILS: Rocky, gravelly; dry. BLOOM: Apr–Jul; red-purple to violet with pink or white tinges. Pallid milkweed (A. cryptoceras) PLANT: Stout prostrate spreading stems, rarely branched; smooth. LEAVES: Opposite, broad oval- to heart-shaped; waxy and smooth. HABITAT: Desert washes, slopes, and hillsides, in pinyon-juniper woodland, sagebrush, salt desert shrublands, and aspen zones. SOILS: Sandy to clayey, gypsum, or serpentine; dry. BLOOM: Apr–Jun; greenish yellow and red or dark violet. Narrowleaf milkweed (A. fascicularis) PLANT: Thin upright branched stems; smooth. LEAVES: Opposite to whorled; narrow to lance-shaped; folded lengthwise; mostly smooth. HABITAT: Grasslands, wetland-riparian areas, chaparral, open forests, banks of streams and irrigation ditches, disturbed areas, fallow fields. SOILS: Sandy to clayey, tolerates saline; dry–moist. BLOOM: May–Oct; dusky pink to rose with touches of white. Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Grasslands and ditches, edges of ponds, lakes, streams (Idaho only). SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jun–Sep; pink, light purple. KEY MAY BE MORE TOLERANT OF MOWING MILKWEEDS OF IDAHO, OREGON & WASHINGTON

F-18 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org Xerces Society for Invertebrate Conservation: xerces.org Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (BREEDING ENERATIONS); 6–9 MONTHS (OVERWINTERING GENERATION) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Other monarch nectar plants in the region: Additional milkweeds that occur rarely in SE Idaho: A. asperula and A. subverticillata. Note: monarchs are less likely to be seen breeding in the region. Including high value monarch nectar plants will support adult monarchs that migrate through the region. Visit xerces.org/monarch- nectar-plants for more monarch nectar plants. Showy milkweed (A. speciosa) PLANT: Stout upright, unbranched stems; hairy. LEAVES: Opposite; broad and oval-shaped; hairy. HABITAT: edges of rivers, ponds. SOILS: Sandy to loamy; dry–moist. BLOOM: May– Canada goldenrod (Solidago canadensis) PLANT: Slow-growing, rhizomatous perennial; 7’ max. LEAVES: hairs. SOILS/HABITAT: Any; moist– wet; meadows, prairies, fallow fields, banks of rivers, streams, ditches. BLOOM: Jul–Oct; yellow. Rubber rabbitbrush (Ericamia nauseosa) PLANT: Shrub with erect, rubbery stems; densely hairy; 8’ max. LEAVES: Alternate; linear; hairy. SOILS/HABITAT: Any; dry; disturbed sites, roadsides, scrub, degraded grasslands, BLOOM: Aug–Oct; yellow. Western goldentop (Euthamia occidentalis) PLANT: Rhizomatous perennial, numerous erect stems; 6’ max. LEAVES: Alternate; narrow, grass- like. SOILS/HABITAT: Loamy, sandy, clayey; wet; marshes/wetlands, meadows, grassland, scrubland, banks of rivers, streams, ditches. BLOOM: Jul–Sep; yellow and green. Common sunflower (Helianthus annuus) PLANT: Annual, single erect stem; coarse with rough hairs; 10’ max. LEAVES: Alternate; oval- to heart- -shaped; with rough hairs. SOILS/ HABITAT: Any; dry; disturbed sites, grasslands, meadows, foothills. BLOOM: Jul–Sep; yellow with red, orange, green, or brown. Maps & Distribution Data: The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Stephanie McKnight, Jennifer Hopwood, and Sara Morris (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: incarnata); Xerces Society / Eric Lee-Mader (Solidago canadensis) Xerces Society / Stephanie McKnight (A. cordifolia, A cryptoceras, A. fascicularis, A. speciosa, Ericamia nauseosa, Helianthus annuus). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces is a trademark registered in the U.S. Patent and Trademark Office. 19-023_01 These profiles are derived from regional floras and field guides and Woodson’s Jonathan Coffin / flickr (Euthamia occidentalis); Tom Potterfield / flickr (A Grasslands, fallow fields, disturbed areas, Aug; pink and cream or white; flowers are the largest of American species. Due to the paucity of native milkweed species in northern portions of the Pacific Northwest, Alternate; lance-shaped; with fine rangeland, fallow fields.

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-19 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. (Continued on next page.) The most common milkweeds in roadsides in Kansas & Missouri (in alphabetical order): Swamp milkweed (A. incarnata) PLANT: One to many upright, branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Moist prairies, marshes, ditches, edges of ponds, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jun–Aug; light to dark pink or rose purple. Common milkweed (A. syriaca) PLANT: One to many stout, upright, unbranched stems; usually with short dense hairs. LEAVES: Opposite; oval-shaped; hairy underneath. HABITAT: Prairies, old fields, railways, open woods, flood plains, disturbed areas. SOILS: Sandy to loamy, clayey or rocky; dry–wet. BLOOM: May–Aug; pink. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Prairies, old fields, glades, open woods. SOILS: Sandy, loamy, rocky; dry– mesic. BLOOM: May–Sep; orange to red or yellow. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or with short hairs. HABITAT: Prairies, open woods, fields, flood plains, glades, railways, disturbed areas. SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: May–Sep; white to green. KEY MAY BE MORE TOLERANT OF MOWING MILKWEEDS OF KANSAS & MISSOURI

F-20 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Kansas and/or Missouri: Asclepias amplexicaulis, A. arenaria, A. asperula ssp. capricornu, A. engelmanniana, A. involucrata, A. lanuginosa, A. latifolia, A. meadii, A. perennis, A. pumila, A. purpurascens, A. quadrifolia, A. speciosa, A. subverticillata, A. variegata. Slimleaf milkweed (A. stenophylla) PLANT: Upright, unbranched stems; 2’ max. LEAVES: Alternate; very narrow to lance-shaped; folded lengthwise; with short hairs. SOILS/ HABITAT: Sandy to rocky; dry; prairies, meadows, glades, bluffs. BLOOM: Jun–Aug; yellow to pale green with touches of white. Green comet milkweed (A. viridiflora) PLANT: Spreading to upright, unbranched stems; with short hairs, 3’ max. LEAVES: Opposite; lance- shaped; edges folded upward or wavy; with short hairs. SOILS/HABITAT: Sandy to loamy or rocky; dry–dry-mesic; prairies, old fields, forests, glades. BLOOM: May–Aug; light to yellowish green. Prairie milkweed (A. sullivantii) PLANT: Upright, unbranched, stout stems; smooth; 4’ max. LEAVES: Opposite; lance- to oval-shaped; very smooth. SOILS/HABITAT: Sandy clay or loamy; mesic–moist; prairies, wet meadows. BLOOM: Jun–Aug; pink with light green or purple. Green milkweed (A. hirtella) PLANT: Upright, unbranched stems; 3’ max. LEAVES: Alternate; long and narrow to lance-shaped; with short hairs. SOILS/HABITAT: Sandy to rocky or clayey; dry–dry-mesic; prairies, open woods, glades, railways. BLOOM: May–Aug; green with purple or cream. Green antelopehorn (A. viridis) PLANT: Multiple upright, unbranched stems; usually smooth. LEAVES: Alternate; lance- to oval-shaped; with wavy margins. HABITAT: Upland prairies, disturbed areas. SOILS: Sandy, rocky, clayey; dry. BLOOM: May–Jul; green with touches of purple. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across both states and are found in roadsides. Less common species might not occur in both states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https:// plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Stephanie Frischie, and Ray Moranz (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Craig Freeman (University of Kansas) and Carol Davit (Missouri Prairie Foundation). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Jim Fowler (A. syriaca); Krista Lundgren, USFWS / flickr (A. viridiflora); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata); Paul Rothrock / SEINet (A. hirtella); Scott Seigfreid (A. tuberosa); Xerces Society / Ray Moranz (A. stenophylla, A. sullivantii). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-024_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-21 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in the Mid-Atlantic Region (in alphabetical order): Clasping milkweed (A. amplexicaulis) PLANT: Upright, unbranched stems; smooth. LEAVES: Opposite; oval- shaped; wavy margins; base of leaves clasp stem. HABITAT: Grasslands, open woodlands and edges. SOILS: Sandy, rocky; dry. BLOOM: Jun–Jul; light to dark pink with cream or light green Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Moist grasslands and ditches, edges of ponds, swamps, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jul–Aug; light to dark pink or rose purple. Common milkweed (A. syriaca) PLANT: One to many stout, upright, unbranched stems; usually with short dense hairs. LEAVES: Opposite; oval-shaped; hairy underneath. HABITAT: Grasslands, old fields, open woods, flood plains, disturbed areas. SOILS: Sandy to loamy, clayey or rocky; dry–wet. BLOOM: Jun-Aug, light purple or pink. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Grasslands, old fields, open woods, pine barrens, disturbed areas. SOILS: Sandy, loamy, rocky; dry–mesic. BLOOM: Jun-Aug, orange to red or yellow. MILKWEEDS OF THE MID-ATLANTIC DELAWARE, DISTRICT OF COLUMBIA, MARYLAND, NEW JERSEY, PENNSYLVANIA, VIRGINIA & WEST VIRGINIA

F-22 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in the Mid-Atlantic: Asclepias exaltata, A. lanceolata, A. longifolia, A. rubra, A. viridis (WV only). Fourleaf milkweed (A. quadrifolia) PLANT: Upright, unbranched stems; with short hairs; 2.5’ max. LEAVES: Opposite (except a false whorl of four leaves in center of stem); oval- shaped; usually smooth. SOILS/HABITAT: Rocky, sandy to loamy; dry; woodlands or woodland edges, glades. BLOOM: May–Jul; white to pink. Green comet milkweed (A. viridiflora) PLANT: Unbranched stems, upright to spreading; with short hairs; 3’ max. LEAVES: Opposite; lance-shaped; edges wavy or folded upward; with short hairs. SOILS/HABITAT: Sandy, loamy, rocky; dry–dry-mesic; grasslands, old fields, dunes, forests, glades. BLOOM: Jun–Sep; light to yellowish green. Redring milkweed (A. variegata) PLANT: Upright, unbranched stems; purplish-green; usually smooth; 3’ max. LEAVES: Opposite; oval- shaped; usually smooth. SOILS/ HABITAT: Sandy, rocky, loamy to clay-loamy; dry– mesic; savannas, woodlands and edges, banks of streams. BLOOM: May-Jun; white to light green, with red or purple ring. Purple milkweed (A. purpurascens) PLANT: Upright, unbranched, stout stems; smooth; 6’ max. LEAVES: Opposite; oval-shaped; smooth above, with fine hairs below. SOILS/ HABITAT: Loamy to clayey; mesic; grasslands, old fields, woodland edges, ditches. BLOOM: Jun– Aug; rich purple. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or with short hairs. HABITAT: Grasslands, open woods, fields, flood plains, disturbed areas. SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: Jul–Sep; white to green. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Stephanie Frischie, Nancy Adamson, and Kelly Gill (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Steve Young. Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Jim Fowler (A. syriaca); Krista Lundgren, USFWS / flickr (A. viridiflora); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata); Paul Rothrock / SEINet (A. amplexicaulis [left]); Scott Seigfreid (A. tuberosa); Vern Wilkins, Indiana University / Bugwood.org (A. quadrifolia); Xerces Society / Nancy Lee Adamson (A. amplexicaulis [right]). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-025_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-23 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in Montana & Wyoming (in alphabetical order): Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Wet meadows, grasslands, ditches, edges of ponds, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet. BLOOM: Jun–Jul; pink, light purple. Plains milkweed (A. pumila) PLANT: Upright, unbranched or branched stems; with fine hairs. LEAVES: Alternate, may appear whorled; thin and narrow; dense on stems (bottlebrush appearance). HABITAT: Prairies, plains, low hills. SOILS: Rocky, sandy, gypseous, calcareous; dry. BLOOM: Jun–Sep; white to pink. Showy milkweed (A. speciosa) PLANT: Stout upright, unbranched stems; hairy. LEAVES: Opposite; oval- shaped; hairy. HABITAT: Grasslands, meadows, fields, disturbed areas, edges of rivers, ponds. SOILS: Sandy to loamy; dry–moist. BLOOM: May–Aug; pink and cream or white; flowers are the largest of North American species. Whorled milkweed (A. verticillata) PLANT: One to several upright, usually unbranched stems; sparsely hairy. LEAVES: Whorled; narrow to thread-like; leaf margins rolled downward; smooth or with short hairs. HABITAT: Grasslands, open woodlands, badlands, plains. SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: Jun–Sep; white to greenish. MILKWEEDS OF MONTANA & WYOMING

F-24 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Montana and Wyoming: Asclepias arenaria, A. cryptoceras, A. engelmanniana, A. syriaca, A. uncialis. Oval-leaf milkweed (A. ovalifolia) PLANT: Upright, unbranched stems; with fine hairs; 2’ max. LEAVES: Opposite; lance- to oval- shaped; fine hairs underneath. SOILS/HABITAT: Sandy, silty loam; dry; prairies, open woods. BLOOM: Jun–Jul; cream or white with pink or yellow. Horsetail milkweed (A. subverticillata) PLANT: Upright branched or unbranched stems; smooth or with fine hairs; 3’ max. LEAVES: Whorled; narrow; smooth. SOILS/ HABITAT: Sandy; moist; plains, hills, disturbed areas, ditches (Wyoming only). BLOOM: May– Aug; yellow to cream or purple. Slimleaf milkweed (A. stenophylla) PLANT: Unbranched, upright stems; 2’ max. LEAVES: Alternate; very narrow to lance-shaped; folded lengthwise; with short hairs. SOILS/ HABITAT: Sandy, rocky; dry; prairies, meadows. BLOOM: Jun–Aug; yellow to pale green with touches of white. Hall’s milkweed (A. hallii) PLANT: Upright, unbranched stem or branched at base; hairy; 2’ max. LEAVES: Alternate to opposite; narrow oval-shaped; hairy. SOILS/ HABITAT: Sandy, gravelly; dry; prairies, wash- bottoms, hills (Wyoming only). BLOOM: Jun–Aug; purple, pink, cream or white with green. Green comet milkweed (A. viridiflora) PLANT: Unbranched stems, spreading to upright; with short hairs; 3’ max. LEAVES: Opposite; lance-shaped; narrow and often with margins folded upward; with short hairs. HABITAT: Grasslands, plains, hills, old fields. SOILS: Sandy to loamy or rocky; dry–dry-mesic. BLOOM: Jun–Jul; light green to green. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across both states and are found in roadsides. Less common species might not occur in both states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https:// plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Stephanie McKnight and Jennifer Hopwood (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by Monica Pokorny (USDA–NRCS Montana) and Aaron Clausen (Pheasants Forever). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Frankia Coburn / SEINet (A. hallii); Max Licher / SEINet (A. subverticillata); Krista Lundgren, USFWS / flickr (A. viridiflora, A. ovalifolia); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata); Xerces Society / Stephanie McKnight (A. speciosa); Xerces Society / Ray Moranz (A. pumilla, A. stenophylla). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-026_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-25 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Moist prairies, marshes, ditches, edges of ponds, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jun–Aug; light to dark pink or rose purple. Showy milkweed (A. speciosa) PLANT: Stout upright, unbranched stems; hairy. LEAVES: Opposite; oval-shaped; hairy. HABITAT: Prairies, old fields, edges of rivers, ponds, disturbed areas. SOILS: Sandy to loamy; dry to slightly wet, prefers moist soils. BLOOM: Jun–Aug; pink and cream or white; flowers are the largest of American species. Common milkweed (A. syriaca) PLANT: One to many erect, stout unbranched stems; usually with short dense hairs. LEAVES: Opposite; oval-shaped; hairy underneath. HABITAT: Prairies, old fields, railways, open woods, flood plains, disturbed areas. SOILS: Sandy to loamy, clayey or rocky; dry–wet. BLOOM: Jun–Aug; pink. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or with short hairs. HABITAT: Prairies, open woods, fields, flood plains, disturbed areas. SOILS: Loamy, sandy, rocky, clayey; dry–mesic. BLOOM: Jun–Sep; white to green. The most common milkweeds in roadsides in Nebraska & The Dakotas (in alphabetical order): MILKWEEDS OF NEBRASKA & THE DAKOTAS

F-26 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Nebraska, North Dakota, and/or South Dakota: Asclepias amplexicaulis, A. asperula ssp. capricornu, A. lanuginosa, A. latifolia, A. sullivantii, A. tuberosa, A. viridis. Oval-leaf milkweed (A. ovalifolia) PLANT: Upright, unbranched stems; with fine hairs; 2’ max. LEAVES: Opposite; lance-shaped to oval-shaped; fine hairs underneath. SOILS/HABITAT: Sandy, silt loam; dry; prairies, open woods. BLOOM: Jun–Aug; cream or white with pink or yellow. Slimleaf milkweed (A. stenophylla) PLANT: Upright, unbranched stems; 2’ max. LEAVES: Alternate to nearly opposite; very thin; folded lengthwise. SOILS/HABITAT: Sandy, rocky; dry; prairies, meadows. BLOOM: Jun–Aug; yellow to pale green with touches of white. Plains milkweed (A. pumila) PLANT: Upright, unbranched to branched stems; 1’ max. LEAVES: Alternate; thin and narrow; dense on stems. SOILS/HABITAT: Sandy, clayey, rocky; dry; prairies, plains, low hills, badlands, floodplains, woods. BLOOM: Jul–Aug; white to greenish white. Sand milkweed (A. arenaria) PLANT: Spreading to upright, unbranched stems; hairy; 6’ max. LEAVES: Opposite; broadly oval- shaped; woolly hairs. SOILS/ HABITAT: Sandy; dry; prairies, rangeland, riverbanks, dunes. BLOOM: Jun–Aug; pale green, yellow or cream with tines of pink or purple. Green comet milkweed (A. viridiflora) PLANT: Unbranched stems, spreading to erect; with short hairs. LEAVES: Opposite; lance-shaped with edges folded upward or wavy; with short hairs. HABITAT: Prairies, old fields, dunes, forests. SOILS: Sandy to loamy or rocky; dry–dry-mesic. BLOOM: May–Jul; light green to yellowish green. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Rae Powers, Sarah Hamilton Buxton, Stephanie Frischie (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by: Mercy Manzanares-Dinwiddie (NE Game and Parks Commission). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTOS: Jim Fowler (A. syriaca); Chris Helzer / The Nature Conservancy (A. arenaria); Krista Lundgren, USFWS / flickr (A. viridiflora, A. ovalifolia); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata); Xerces Society / Stephanie McKnight (A. speciosa); Xerces Society / Ray Moranz (A. pumilla, A. stenophylla). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-027_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-27 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in Nevada & Utah (in alphabetical order): Spider milkweed (A. asperula ssp. asperula) PLANT: Multiple spreading stems, unbranched to few branches; usually smooth. LEAVES: Alternate; lance-shaped; usually folded lengthwise. HABITAT: Grasslands, disturbed areas. SOILS: Clayey, gravelly, sandy, rocky limestone, dry. BLOOM: Apr–Jun; light green with touches of purple. Desert milkweed (A. erosa) PLANT: Upright, unbranched to branched stout stems; with fine hairs; grows in clumps. LEAVES: Opposite; oval- to lance-shaped; smooth or with HABITAT: Washes, gulches, canyons, disturbed areas in deserts, creosote bush and sagebrush communities. SOILS: Sandy; dry. BLOOM: Narrowleaf milkweed (A. fascicularis) PLANT: Thin upright branched stems; smooth. LEAVES: Opposite to whorled; narrow to lance-shaped; folded lengthwise; mostly smooth. HABITAT: Grasslands, wetland-riparian areas, open woodlands, chaparral, sagebrush, SOILS: Sandy to clayey, tolerates saline; dry–moist. BLOOM: May–Oct; dusky pink to rose with touches of white. Showy milkweed (A. speciosa) PLANT: Stout upright, unbranched stems; hairy. LEAVES: Opposite; oval- shaped; hairy. HABITAT: rivers, ponds. SOILS: Sandy to loamy; dry–moist. BLOOM: May–Aug; pink MILKWEEDS OF NEVADA & UTAH essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. fine hairs. Apr—Oct; yellowish or cream; flower buds are hairy. disturbed areas, banks of streams and irrigation ditches, fallow fields. Grasslands, old fields, disturbed areas, edges of and cream or white; flowers are the largest of American species.

F-28 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Nevada & Utah: Asclepias cordifolia, A. cutleri, A. engelmanniana, A. hallii, A. involucrata, A. macrosperma, A. nyctaginifolia, A. rusbyi, A. ruthiae, A. subulata, A. syriaca, A. tuberosa, A. uncialis, A. welshii. Swamp milkweed (A. incarnata) PLANT: One to many upright, branched stems; smooth or with short hairs; 5’ max. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. SOILS/HABITAT: Silty to loamy or clayey; moist–wet; grasslands, ditches, edges of ponds, lakes, streams. BLOOM: Jun–Sep; pink, light purple. Utah milkweed (A. labriformis) PLANT: Multiple upright, usually unbranched, stems; smooth; 1.5’ max. LEAVES: Opposite; lance- shaped to narrow; with a patch of coarse hairs. SOILS/HABITAT: Sandy; dry with moist subsoil; washes, canyons, gulches, disturbed areas, desert shrub. BLOOM: May–Aug; pale yellow-green to white. Broadleaf milkweed (A. latifolia) PLANT: Upright, unbranched, stout stems; woolly when young, smooth with age; 2’ max. LEAVES: Opposite; oval-shaped; woolly when young, smooth with age. SOILS/HABITAT: Sandy, clayey, rocky; dry; grasslands, chaparral, hillside woodlands, canyons. BLOOM: May–Aug; white to pale green. Pallid milkweed (A. cryptoceras) PLANT: Stout, prostrate, spreading stems, rarely branched; smooth; 1’ max. LEAVES: Opposite; broad oval- to heart-shaped; waxy, smooth. SOILS/ HABITAT: Sandy to clayey; dry; washes, hillsides, woodland, sagebrush, salt desert shrubland. BLOOM: Apr–Jun; greenish yellow and red or dark violet. Horsetail milkweed (A. subverticillata) PLANT: Upright, branched or unbranched stems; smooth or with fine hairs. LEAVES: Whorled; narrow to needle-like; smooth. HABITAT: Ditches, disturbed areas, stream edges. SOILS: Sandy; moist. BLOOM: May–Aug; yellow to cream or purple. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across both states and are found in roadsides. Less common species might not occur in both states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https:// plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Stephanie McKnight, Jennifer Hopwood (Xerces Society), Alison Cariveau (Monarch Joint Venture). Reviewed by Rachel Williams (USFWS). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Frankie Coburn / SEINet (A. labriformis); Max Licher / SEINet (A. subverticillata, A. latifolia); Tom Potterfield / flickr (A. incarnata); Xerces Society / Stephanie McKnight (A. erosa, A. fascicularis, A. speciosa, A. cryptoceras); Andrey Zharkikh / flickr (A. a. ssp. asperula). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-028_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-29 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) The most common milkweeds in roadsides in the Northeast Region (in alphabetical order): Swamp milkweed (A. incarnata) PLANT: One to many upright, branched stems; smooth or with short hairs. LEAVES: Opposite; lance-shaped or narrow; with few short hairs. HABITAT: Moist grasslands and ditches, edges of ponds, swamps, lakes, streams. SOILS: Silty to loamy or clayey; moist–wet, tolerates some mesic. BLOOM: Jul–Aug; pink or light purple. Common milkweed (A. syriaca) PLANT: One to many stout, upright, unbranched stems; usually with short dense hairs. LEAVES: Opposite; oval-shaped; hairy underneath. HABITAT: Grasslands, old fields, open woods, flood plains, disturbed areas. SOILS: Sandy to loamy, clayey or rocky; dry–wet. BLOOM: Jul–Aug; pale purple or pink. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Grasslands, open woods, pine barrens. SOILS: Sandy, loamy, rocky; dry– mesic. BLOOM: Jun–Jul; orange to red or yellow. Clasping milkweed (A. amplexicaulis) PLANT: Upright, unbranched stems; smooth; 3’ max. LEAVES: Opposite; oval-shaped; wavy margins; base of leaves clasp stem. SOILS: Sandy, rocky; dry. HABITAT: Grasslands, open woodlands and edges. BLOOM: Jun–Jul; light to dark pink with cream or light green. Less common roadside milkweeds: MILKWEEDS OF THE NORTHEAST CONNECTICUT, MAINE, MASSACHUSETTS, NEW HAMPSHIRE, NEW YORK, RHODE ISLAND & VERMONT

F-30 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Less common roadside milkweeds continued Additional milkweeds in the Northeast: Asclepias purpurascens, A. rubra, A. variegata, A. viridiflora. Poke milkweed (A. exaltata) PLANT: Upright, unbranched stem; smooth; 6’ max. LEAVES: Opposite; oval-shaped; smooth. SOILS: Sandy, loamy; dry. HABITAT: Woodlands or woodland edges, dry rocky summits. BLOOM: Jun–Jul; green or pale purple with white or light pink; drooping. Fourleaf milkweed (A. quadrifolia) PLANT: Upright, unbranched stems; with short hairs; 2.5’ max. LEAVES: Opposite, except a false whorl of four leaves in center of stem; oval- shaped; usually smooth. SOILS: Rocky, sandy to loamy; dry. HABITAT: Open woodlands or woodland edges, glades. BLOOM: May–Jun; white to pink. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs; 3’ max. LEAVES: Whorled; narrow to needle-like; smooth or short hairs. SOILS: Sandy, rocky, clayey; moist. HABITAT: Grasslands, open woods, fields, flood plains, disturbed areas. BLOOM: Jul-Aug; white to green. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Stephanie Frischie, Kelly Gill, Katie Hietala- Henschell, Eric Venturini, Emily May (Xerces Society), Alison Cariveau (Monarch Joint Venture). Reviewed by Steve Young (NY NHP), Shawnna Clark (USDA NRCS). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Jim Fowler (A. syriaca, A. exaltata); Jerry Oldenettel / flickr (A. verticillata); Tom Potterfield / flickr (A. incarnata); Xerces Society / Nancy Lee Adamson (A. amplexicaulis [right]); Paul Rothrock / SEINet (A. amplexicaulis [left]); Scott Seigfreid (A. tuberosa); Vern Wilkins, Indiana University / Bugwood.org (A. quadrifolia). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-029_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-31 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an (Continued on next page.) Antelopehorns (A. asperula ssp. capricornu) PLANT: Multiple spreading stems, unbranched to few branches; usually smooth. LEAVES: Alternate; lance-shaped; usually folded lengthwise. HABITAT: Prairies, disturbed areas. SOILS: Sandy, rocky limestone, clayey, gravelly; dry. BLOOM: Apr–Sep; light green with touches of purple. Broadleaf milkweed (A. latifolia) PLANT: Upright, unbranched, stout stems; woolly when young to smooth with age. LEAVES: Opposite; oval-shaped; woolly when young to smooth with age. HABITAT: Prairie, disturbed areas. SOILS: Sandy, clayey, rocky; dry. BLOOM: May–Aug; white to pale green. Zizotes milkweed (A. oenotheroides) PLANT: Spreading to upright branched stout stems; smooth. LEAVES: Opposite; wavy edges. HABITAT: periodic mowing and drought. SOILS: Sandy, rocky; dry. BLOOM: Apr–Nov; green with white and/or purple. The most common milkweeds in roadsides in Oklahoma & Texas (in alphabetical order): Green comet milkweed (A. viridiflora) PLANT: Unbranched stems, spreading to erect; with short hairs. LEAVES: Opposite; lance- to oval-shaped with edges folded upward or wavy; with short hairs. HABITAT: SOILS: Sandy to loamy or rocky; dry–dry-mesic. BLOOM: Jun–Aug; light green to yellowish green. KEY MAY BE MORE TOLERANT OF MOWING MILKWEEDS OF OKLAHOMA & TEXAS essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. Rocky prairies, old fields, dunes, forests, glades.Prairies, ditches, fields, dunes; may survive

F-32 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Western Monarch Milkweed Mapper: www.monarchmilkweedmapper.org ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in Oklahoma and/or Texas: Asclepias arenaria, A. brachystephana, A. emoryi, A. glaucescens, A. hirtella, A. incarnata, A. involucrata, A. lanceolata, A. linearis, A. macrotis, A. nummularia, A. obovata, A. prostrata, A. perennis, A. pumila, A. purpurascens, A. rubra, A. scaposa, A. speciosa, A. sperryi, A. subverticillata, A. syriaca, A. texana, A. tomentosa, A. uncialis, A. variegata, A. verticillata. Engelmann’s milkweed (A. engelmanniana) PLANT: One to a few upright, usually unbranched, stout stems; smooth; 3’ max. LEAVES: Alternate; narrow and linear; smooth. SOILS/HABITAT: Sandy, rocky or calcareous; dry; grasslands, savannas, woodlands, riparian areas. BLOOM: May–Sep; small, yellowish-green with purple. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; no milky sap; 3’ max. LEAVES: Alternate; lance-shaped; hairy underneath. SOILS/HABITAT: Sandy, loamy, rocky; well-drained; prairies, old fields, open woods. BLOOM: Apr–Sep; orange to red or yellow. Slimleaf milkweed (A. stenophylla) PLANT: Unbranched, upright stems; 2’ max. LEAVES: Alternate; very narrow to lance-shaped; folded lengthwise; with short hairs. SOILS/HABITAT: Sandy, rocky; dry; prairies, meadows. BLOOM: Jun– Aug; yellow to pale green with touches of white. Clasping milkweed (A. amplexicaulis) PLANT: Unbranched, upright stems; smooth; 3’ max. LEAVES: Opposite; oval-shaped; wavy margins; base of leaves clasp stem. SOILS/HABITAT: Sandy; dry; grasslands, savannas, woodland edges. BLOOM: Apr–Jun; green with pink or purple. Green antelopehorn (A. viridis) PLANT: Multiple unbranched upright stems; usually smooth. LEAVES: Alternate; lance-shaped to oval-shaped; with wavy margins. HABITAT: Upland prairies, open woods, disturbed areas. SOILS: Sandy, rocky, clayey; dry. BLOOM: Mar–Sep; green with touches of purple. Maps & Distribution Data: These profiles are derived from regional floras and field guides and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across both states and are found in roadsides. Less common species might not occur in both states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https:// plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Ray Moranz, Jennifer Hopwood, and Stephanie Frischie (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Reviewed by: Kristen Baum, Oklahoma State University; Jason Singhurst, Texas Parks and Wildlife Department. Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Patrick Alexander / SEINet (A. oenotheroides); Jim Fowler (A. asperula ssp. capricornu [right], A. latifolia); Max Licher / SEINet (A. engelmanniana); Krista Lundgren, USFWS / flickr (A. viridiflora); Paul Rothrock / SEINet (A. amplexicaulis); Scott Seigfreid (A. tuberosa); Richard Spellengberg / Calphotos (A. asperula ssp. capricornu [left]); Xerces Society / Ray Moranz (A. stenophylla). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-030_01

Regionally Specific Roadside Milkweed Recognition Fact Sheets F-33 Milkweeds (Asclepias spp.) are herbaceous perennial plants named for their milky sap. These plants occur in a wide range of habitats, including intact natural communities on roadsides and highly disturbed roadsides. As required host plants for monarch (Danaus plexippus) caterpillars, milkweeds play an essential role in the butterfly’s life cycle (see reverse). Vegetation management that allows milkweeds to persist can support monarchs. This guide can help you recognize the most common native species found on roadsides in your region. KEY MAY BE MORE TOLERANT OF MOWING (Continued on next page.) Clasping milkweed (A. amplexicaulis) PLANT: Upright, unbranched stems; smooth. LEAVES: Opposite; oval- shaped; wavy margins; base of leaves clasp stem. HABITAT: Sandhills, grasslands, savannas, woodland edges. SOILS: Sandy, gravelly; dry. BLOOM: May–Jul; light to dark pink with cream or green; fragrance of cloves and roses. Butterfly milkweed (A. tuberosa) PLANT: One to many spreading to upright stems; with short hairs; lacks milky sap. LEAVES: Alternate; lance-shaped; hairy underneath. HABITAT: Grasslands, old fields, open woods, pine barrens. SOILS: Sandy, loamy, rocky; dry–mesic. BLOOM: May–Sep; orange to red or yellow. Redring milkweed (A. variegata) PLANT: Upright, unbranched stems; purplish-green; usually smooth. LEAVES: Opposite; oval-shaped; usually smooth. HABITAT: Savannas, rocky woodlands and edges, banks of streams; part shade. SOILS: Sandy, rocky, loamy to clay-loam; dry–mesic. BLOOM: May–Jul; white or cream, with red or purple ring. Whorled milkweed (A. verticillata) PLANT: One to several upright, unbranched stems; with short hairs. LEAVES: Whorled; narrow to needle-like; smooth or short hairs. HABITAT: Grasslands, open woods, disturbed areas, barrens, sandhills, rock outcrops (especially mafic rocks). SOILS: Sandy, rocky, clayey; dry–mesic. BLOOM: May–Sep; white or cream with green. The most common milkweeds in roadsides in the Southeast Region (in alphabetical order): MILKWEEDS OF THE SOUTHEAST ALABAMA, KENTUCKY, SOUTH CAROLINA, TENNESSEE, GEORGIA & NORTH CAROLINA

F-34 Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies Additional Resources: ӧ For more information on monarchs and roadsides, including monitoring, visit: tinyurl.com/MJV-Monarchs-Roadsides ӧ Mowing and Monarchs: tinyurl.com/MJV-MowingForMonarchs ӧ Xerces Society for Invertebrate Conservation: xerces.org ӧ Monarch Joint Venture: monarchjointventure.org Multiple generations of monarchs are produced over the spring and summer, with the fall generation migrating to overwintering sites. You can monitor monarchs or milkweeds; see Additional Resources above. 1 Egg 3–5 DAYS 2 Larva 10–14 DAYS 3 Chrysalis 10–14 DAYS 4 Adult 2–5 WEEKS (breeding generations); 6–9 MONTHS (overwintering generation) Caterpillar grows by molting 5 INSTARS THE MONARCH BUTTERFLY LIFE CYCLE Most common milkweed species continued Less common roadside milkweeds: Additional milkweeds in the Southeast: Asclepias cinerea, A. connivens, A. exaltata, A. hirtella, A. lanceolata, A. michauxii, A. obovata, A. pedicellata, A. perennis, A. purpurascens, A. quadrifolia, A. rubra, A. tomentosa, A. viridis, A. viridula. Swamp milkweed (A. incarnata) PLANT: One to many upright branched stems; smooth or with short hairs; 5’ max. LEAVES: Opposite; lance- shaped or narrow; with sparse short hairs. SOILS/HABITAT: Silty, loamy, clayey; moist–wet; grasslands, ditches, edges of lakes, streams. BLOOM: Jul–Sep; light to dark pink or rose purple. Common milkweed (A. syriaca) PLANT: One to many stout, upright, unbranched stems; with short dense hairs; 5’ max. LEAVES: Opposite; oval-shaped; hairy underneath. SOILS/HABITAT: Sandy to loamy, clayey or rocky; dry–wet; grasslands, disturbed areas, railways, edges of lakes, ponds, streams. BLOOM: Jun–Aug; pink. Longleaf milkweed (A. longifolia) PLANT: Upright, unbranched slender stem; with few hairs; 3’ max. LEAVES: Alternate; narrow and lance-shaped; with few hairs. SOILS/HABITAT: Sandy to loamy or loam-clay; wet; pinelands, savannas, swamps. BLOOM: May– Jun; dark pink and white, tipped with green. Pinewoods milkweed (A. humistrata) PLANT: One to multiple sprawling stems; usually smooth; 3’ max. LEAVES: Opposite; oval-shaped; base of leaves clasp stem; purple veins; usually smooth. SOILS/HABITAT: Sandy; dry; open woods, sandhills, scrubland, pastures. BLOOM: Mar–Jun; pink to white flowers. Green comet milkweed (A. viridiflora) PLANT: Unbranched stems, spreading to upright; with short hairs. LEAVES: Opposite; lance-shaped with edges folded upward or wavy; with short hairs. HABITAT: Open woodlands, woodland edges, barrens, grasslands, glades (especially over mafic or calcareous rocks). SOILS: Sandy to loamy or rocky; dry–dry-mesic. BLOOM: May–Aug; light green to yellowish green with pink. Maps & Distribution Data: These profiles are derived from regional floras and field guides (e.g., Weakley 2019) and Woodson’s The North American Species of Asclepias (1954). Most common species are abundant across the states and are found in roadsides. Less common species might not occur in all states, have a limited distribution across a state, or may be less common in roadsides. Additional species may be uncommon in roadsides, have a small distribution in a state or region, or are uncommon or rare. The range maps indicate counties where species have been observed (but may be incomplete), and were created by USDA-NRCS using the latest data from the USDA’s PLANTS database (https://plants.sc.egov.usda.gov). ACKNOWLEDGMENTS: Written by Jennifer Hopwood, Nancy Lee Adamson, Ray Moranz, and Stephanie Frischie (Xerces Society), and Alison Cariveau (Monarch Joint Venture). Design, header, and monarch life cycle by Sara Morris (Xerces Society). This work was conducted in the National Cooperative Highway Research Program, which is administered by the Transportation Research Board of the National Academies of Sciences, Engineering, and Medicine. PHOTO CREDITS: Jim Fowler (A. syriaca, A. longifolia); Mary Keim / flickr (A. humistrata, A. incarnata); Krista Lundgren, USFWS / flickr (A. viridiflora); Jerry Oldenettel / flickr (A. verticillata); Karan A. Rawlins, University of Georgia / Bugwood.org (A. variegata); Xerces Society / Nancy Lee Adamson (A. amplexicaulis [right]); Paul Rothrock / SEINet (A. amplexicaulis [left]); Scott Seigfreid (A. tuberosa). Photographs remain under the copyright of the photographer. © 2019 by The Xerces Society for Invertebrate Conservation. Xerces® is a trademark registered in the U.S. Patent and Trademark Office. 19-031_01

Abbreviations and acronyms used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FAST Fixing America’s Surface Transportation Act (2015) FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012) NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005) TCRP Transit Cooperative Research Program TDC Transit Development Corporation TEA-21 Transportation Equity Act for the 21st Century (1998) TRB Transportation Research Board TSA Transportation Security Administration U.S. DOT United States Department of Transportation

TRA N SPO RTATIO N RESEA RCH BO A RD 500 Fifth Street, N W W ashington, D C 20001 A D D RESS SERV ICE REQ U ESTED N O N -PR O FIT O R G . U .S. PO STA G E PA ID C O LU M B IA , M D PER M IT N O . 88 Evaluating the Suitability of Roadw ay Corridors for U se by M onarch Butterflies N CH RP Research Report 942 TRB ISBN 978-0-309-48132-8 9 7 8 0 3 0 9 4 8 1 3 2 8 9 0 0 0 0