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17 Beautiful Iowa Milkweeds (Asclepias spp.) to Grow for Monarch Butterflies

Iowa Milkweed Species to Include in your Butterfly Garden

There are seventeen native species of Iowa milkweeds (Asclepias spp.) that can be grown for Monarch Butterflies and other insects. Milkweeds are an important host species for Monarch, Queen, and Soldier Butterflies. The Monarch butterfly in particular uses the cardenolides found in the milky sap of milkweeds to give an unpleasant taste to predators. These plants are also an important nectar source to all insects visiting your pollinator garden.

List of Native Iowa Milkweeds

1. Clasping Milkweed (Asclepias amplexicaulis), a Milkweed for Dry Soils

Clasping Milkweed (Asclepias amplexicaulis): Clasping milkweed is native mostly in eastern Iowa with scattered locations in the west (Kartesz 2015). In the wild, Clasping milkweed grows in dry woodlands, prairies, meadows, and roadsides having sandy or gravelly soil. Growing up to 3 feet tall, this plant has greenish-pink, red, brown, to purple flowers that bloom from March to September.

In Iowa butterfly garden, clasping milkweed is hardy in zones 3-9 and can be grown in places with full sun to part-shade having dry sandy soil. Seeds of clasping milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Plant of clasping milkweed (Asclepias amplexicaulis) with pink flowers in a wooded area.
Clasping Milkweed in a wooded area — Mason Brock (Masebrock), Public domain, via Wikimedia Commons
Pinkish flowers of clasping milkweed (Asclepias amplexicaulis) in a field.
Pink Flowers of Clasping Milkweed — cassi saari, CC BY-SA 4.0, via Wikimedia Commons
Reddish-pink flowers of clasping milkweed (Asclepias amplexicaulis) in a field.
Pinkish Flowers of Clasping Milkweed — “Asclepias amplexicaulis – Clasping Milkweed” by FritzFlohrReynolds is licensed under CC BY-SA 2.0.

2. Engelmann’s Milkweed (Asclepias engelmanniana), a Milkweed for Dry Soils

Engelmann’s Milkweed (Asclepias engelmanniana): Englemann’s milkweed is native and rare in three western counties in Iowa (Kartesz 2015). In the wild, Engelmann’s milkweed grows in dry prairies, plains, canyons, on creek banks, and open woodlands. Growing from 2 to 5 feet tall, this plant has greenish-yellow to purplish flowers that bloom from May to September.

In your Iowa butterfly garden, Engelmann’s milkweed requires full sun, dry sandy or limestone soils and is hardy in zones 5-9. Seeds of Engelmann’s milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Greenish-white flower cluster of engelmann's milkweed (Asclepias engelmanniana).
Flower Cluster of Engelmann’s Milkweed — Asclepias engelmanniana Woodson observed in United States of America by calinsdad (licensed under CC0 1.0)
Plant of Engelmann's milkweed (Asclepias engelmanniana) in an open area.
Plant of Engelmann’s Milkweed in a Field — Asclepias engelmanniana Woodson observed in United States of America by calinsdad (licensed under CC0 1.0)
Flowers of Engelmann's milkweed (Asclepias engelmanniana).
Plant of Engelmann’s Milkweed in a Field — Asclepias engelmanniana Woodson observed in United States of America by calinsdad (licensed under CC0 1.0)

3. Poke Milkweed (Asclepias exaltata), a Milkweed for Shade and Moist Soil

Poke Milkweed (Ascelpias exaltata): Poke milkweed is native generally in eastern Iowa (Kartesz 2015). In the wild, this milkweed is found moist woods, roadsides, and the edges of woods. Growing 2 to 6 feet tall, it is one of the taller milkweeds, and has flowers that are white to green with accents of rose, purple, or blue. The flowers bloom from April to August.

In your Iowa butterfly garden, poke milkweed is hardy in zones 3-9, requires part-shade to shade, and moist soil. Poke milkweed seeds can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Greenish-white flowers of poke milkweed (Asclepias exaltata) in a wooded area.
Flowers of Poke Milkweed (Asclepias exaltata) — Dendroica cerulea, CC BY 2.0, via Wikimedia Commons
Plant of poke milkweed with white flowers in a wooded habitat.
Plant of Poke Milkweed in a Wooded Area — “Asclepias exaltata” by kevinliam is marked with CC0 1.0.
White flowers of poke milkweed (Asclepias exaltata) in a wooded area.
Poke Milkweed (Asclepias exaltata) with White Flowers — homeredwardprice, CC BY 2.0, via Wikimedia Commons

4. Swamp Milkweed (Asclepias incarnata), a Milkweed for Moist Soils

Swamp Milkweed (Asclepias incarnata): Swamp milkweed has two subspecies, ssp. incarnata and ssp. pulchra. The former is found throughout the state (hardy in zones 3-9), while the latter is not found in Illinois (Kartesz 2015). Like the name suggests in the wild, swamp milkweed is found in wet places such as the shores of streams, lakes, ponds, and other wetlands. This is one of the taller milkweeds growing from 3 to 5 feet tall. The flowers, which bloom from July to September are generally a pink to red color, but there is also a white cultivar (pictured below).

In Iowa butterfly garden, swamp milkweed requires full sun to part-shade and prefers moist to medium moisture soil, but can exist in drier soil as a landscape plant. Seeds of swamp milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Pink flowers of swamp milkweed (Asclepias incarnata) from Pennsylvania.
Swamp Milkweed (Asclepias incarnata) with Pink Flowers — Cbaile19, CC0, via Wikimedia Commons
Swamp milkweed (Asclepias incarnata) 'Ice Ballet' cultivar.
‘Ice Ballet’ Cultivar of Swamp Milkweed — Photo by and (c)2009 Derek Ramsey (Ram-Man), GFDL 1.2, via Wikimedia Commons
Follicles (fruits) of swamp milkweed (Asclepias incarnata) in a garden.
Follicles — “Swamp milkweed, rose milkweed, asclepias incarnata, new England native garden” by sapienssolutions is licensed under CC BY 2.0.

5. Side-Cluster Milkweed (Asclepias lanuginosa), a Rare Iowa Milkweed

Side-cluster Milkweed (Asclepias lanuginosa): Side-cluster milkweed is native and rare in scattered locations around Iowa (Kartesz 2015). In the wild, Side-cluster milkweed grows in prairies and sandhills having full sun. The height of this milkweed is variable and ranges from 0.5 to 4 feet tall. The flowers range in color from green to cream and bloom from May to July.

In your Iowa butterfly garden, while side-cluster milkweed is hardy in zones 4-7, it is rare throughout most its range and is not in the horticultural trade.

Plant of side-cluster milkweed (Asclepias lanuginosa).
Vegetative Plant of Side-Cluster Milkweed — Asclepias lanuginosa Nutt. observed in Canada by Chris Friesen (licensed under CC BY 4.0)
Close-up of yellowish-green flowers of side-cluster milkweed (Asclepias lanuginosa).
Yellowish Flowers of Side-Cluster Milkweed — Asclepias lanuginosa Nutt. observed in Canada by Chris Friesen (licensed under CC BY 4.0)
Plants of side-cluster milkweed (Asclepias lanuginosa) with white flowers.
Side-Cluster Milkweed with Yellow Flowers — Asclepias lanuginosa Nutt. observed in Canada by Chris Friesen (licensed under CC BY 4.0)

6. Long-leaf Milkweed (Asclepias longifolia), a Milkweed for Moist Soils

Long-leaf Milkweed (Asclepias longifolia): Long-leaf milkweed has two varieties, var. hirtella and var. longifolia. Of these var. hirtella is native mostly in eastern Iowa (Kartesz 2015). In the wild, long-leaf milkweed grows in moist areas and wetlands such as bogs, swamps, flatwoods, and prairies having full sun. Growing from 1 to 2.5 feet tall, the greenish-white flowers bloom from April to July.

In your Iowa butterfly garden, long-leaf milkweed requires full sun, moist to wet soils and is hardy in zones 4-9.

Purple flowers of long-leaf milkweed (Asclepias longifolia).
Long-leaf Milkweed with Purple Flowers — Asclepias longifolia Michx. observed in United States of America by Justin (licensed under CC0 1.0)
Yellowish-pink flowers of long-leaf milkweed (Asclepias longifolia).
Yellowish Flowers of Long-leaf Milkweed — Public Domain Image
Pink flower cluster of long-leaf milkweed (Asclepias longifolia) in an open area.
Plants of Long-leaf Milkweed in an Open Area — Asclepias longifolia Michx. observed in United States of America by cnagele (licensed under CC0 1.0)

7. Mead’s Milkweed (Asclepias meadii), a Rare Iowa Milkweed

Mead’s Milkweed (Asclepias meadii): Mead’s milkweed is native and rare in southwest and eastern Iowa (Kartesz 2015). In the wild, Mead’s milkweed grows in tallgrass prairies, hay meadows, and barrens having full sun. Growing from 1 to 3 feet tall, the greenish-white to yellow flowers bloom from June to July. This plant is federally endangered and is not in cultivation.

Vegetative plant of mead's milkweed (Asclepias meadii).
“mead’s milkweed” by Ryan Sorrells is licensed under CC BY 4.0.
Close-up of yellowish flowers of mead's milkweed (Asclepias meadii).
Yellow Flowers of Mead’s Milkweed (Asclepias meadii) — Jason Sturner 72, CC BY 2.0, via Wikimedia Commons
Herbarium specimen of Mead's milkweed (Asclepias meadii).
Herbarium Specimen — Asclepias meadii Torr. ex A.Gray collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)

8. Oval-leaf Milkweed (Asclepias ovalifolia), a Milkweed for Well-drained High pH Soil

Oval-leaf Milkweed (Asclepias ovalifolia): Oval-leaf milkweed is native to scattered locations in the state (Kartesz 2015). In the wild, oval-leaf milkweed grows in open areas having full sun or partial shade such as prairies, grasslands, savannas, railroad edges, and alluvial terraces. It is one of the shorter milkweeds in Iowa and grows to about 2 feet tall and has white, pink, or green flowers that bloom from May to August.

In your Iowa butterfly garden, oval-leaf milkweed is hardy in zones 5-9, requires full sun to part-shade and well-drained high pH soil. Oval-leaf milkweed seeds can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Plant of oval-leaf milkweed (Asclepias ovalifolia) with white flowers.
Oval-leaf Milkweed with White Flowers — Asclepias ovalifolia Decne. observed in United States of America by msieges (licensed under CC0 1.0)
Pinkish-white flowers of oval-leaf milkweed (Asclepias ovalifolia).
Flowers of Oval-leaf Milkweed — Justin Meissen from St Paul, United States, CC BY-SA 2.0, via Wikimedia Commons
Plant of oval-leaf milkweed (Asclepias ovalifolia) in a field.
Oval-leaf Milkweed (Ascelpias ovalifolia) in a field — USFWS Mountain-Prairie, CC BY 2.0, via Wikimedia Commons

9. Purple Milkweed (Asclepias purpurascens), a Milkweed for Moist Soils

Purple Milkweed (Asclepias purpurascens): Purple milkweed is native in eastern, central, and southern Iowa (Kartesz 2015). In the wild, purple milkweed grows in moist to dry places having full sun to part shade such as swamps, woodlands, meadows, roadsides, and dry fields. Growing up to 6 feet tall the purple to pink flowers bloom from May to July.

In your Iowa butterfly garden, purple milkweed is hardy in zones 3-8 and requires part-shade but can handle full sun. Soils should be moist and well-drained, but dry soil can be tolerated. Seeds of purple milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Close-up of pinkish-purple flowers of purple milkweed (Asclepias purpurascens).
Pinkish-purple Flowers of Purple Milkweed — Steepcone, Public domain, via Wikimedia Commons
Plants of purple milkweed (Asclepias purpurascens).
Group of Purple Milkweed (Asclepias purpurascens) in a garden — peganum from Henfield, England, CC BY-SA 2.0, via Wikimedia Commons
Plant of purple milkweed (Asclepias purpurascens) with purple flowers.
Purple Milkweed with Purple Flowers — Asclepias purpurascens L. observed in United States of America by Jim Bowhay (licensed under CC0 1.0)

10. Four-leaf Milkweed (Asclepias quadrifolia), a Milkweed for Dry Rocky Soils

Four-leaf Milkweed (Asclepias quadrifolia): Four-leaf milkweed is native primarily in southeastern Iowa, with a scattered distribution in the south central area (Kartesz 2015). In the wild, four-leaf milkweed grows in open places with full sun such as roadsides, pastures, and prairies. Growing from 1 to 3 feet tall, four-leaf milkweed has cream to pink flowers that bloom from April to July.

In your Iowa butterfly garden, four-leaf milkweed is hardy in zones 5-8 and grows best in places of full sun to part-shade with dry rocky soils.

Plant of four-leaf milkweed (Asclepias quadrifolia) in a wooded area.
Four-leaf Milkweed with lavender flowers — User:Halpaugh, CC BY-SA 3.0, via Wikimedia Commons
Pinkish flowers of four-leaf milkweed (Asclepias quadrifolia).
Four-leaf Milkweed with Pink Flowers — User:Halpaugh, CC BY-SA 3.0, via Wikimedia Commons
Plant of four-leaf milkweed (Asclepias quadrifolia) in a wooded area.
Four-leaf Milkweed in a wooded area — “Asclepias quadrifolia” by kodendakj is marked with CC0 1.0.

11. Showy Milkweed (Asclepias speciosa), a Milkweed for Medium to Dry Soils

Showy Milkweed (Asclepias speciosa): Showy milkweed is native and rare in the northwestern part of the state (Kartesz 2015). In the wild, Showy milkweed grows in open places with full sun such as fields, roadsides, and woodlands that are mesic to dry. Growing from 1 to 3 feet tall, this plant has purple to pink flowers that bloom from April to June.

In your Iowa butterfly garden, showy milkweed is hardy in zones 3-9 and requires places of full sun having medium to dry well-drained soil. Seeds of showy milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Pinkish flowers of showy milkweed (Asclepias speciosa).
Showy Milkweed (Asclepias speciosa) with Pink Flowers — Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, via Wikimedia Commons
Pinkish-white flowers of showy milkweed (Asclepias speciosa).
Close-up of Pink Flowers of Showy Milkweed — Asclepias speciosa Torr. observed in Canada by markeambard (licensed under CC0 1.0)
Follicle of showy milkweed (Asclepias speciosa).
Showy Milkweed Follicle — John Rusk from Berkeley, CA, United States of America, CC BY 2.0, via Wikimedia Commons

12. Slim-leaf Milkweed (Asclepias stenophylla), a Milkweed for Dry Soils

Slim-leaf Milkweed (Asclepias stenophylla): Slim-leaf milkweed is native and rare in the western part of the state (Kartesz 2015). In the wild, Slim-leaf milkweed grows in open areas with full sun such as prairies and sandy areas. Growing from 0.5 to 3 feet tall, this milkweed has greenish-white flowers that bloom from June to August.

In your Iowa butterfly garden, slim-leaf milkweed is hardy in zones 3-9, requires full sun, and dry sandy or gravelly soils. Seeds of slim-leaf milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Plant of slim-leaf milkweed (Asclepias stenophylla).
Yellowish Flowers of Slim-leaf Milkweed — Asclepias stenophylla A.Gray observed in United States of America by Craig Martin (licensed under CC0 1.0)
Close-up of Yellowish flowers of slim-leaf milkweed (Asclepias stenophylla).
Slim-leaf Milkweed (Asclepias stenophylla) with yellow flowers — Samuel A. Schmid, CC BY 4.0, via Wikimedia Commons
Plant of slim-leaf milkweed (Asclepias stenophylla) in an open area.
Slim-leaf Milkweed in an open area — Asclepias stenophylla A.Gray observed in United States of America by Craig Martin (licensed under CC0 1.0)

13. Sullivant’s Milkweed (Asclepias sullivantii), a Milkweed for Medium to Dry Soils

Sullivant’s Milkweed (Asclepias sullivantii): Sullivant’s milkweed is native throughout the state (Kartesz 2015). In the wild, Sullivant’s milkweed grows in open areas with full sun such as prairies, meadows, roadsides, and railroads. Growing from 2 to 5 feet tall, it has pink to purplish flowers the pink to purplish flowers that bloom from June to July.

In your Iowa butterfly garden, Sullivant’s milkweed is hardy in zones 3-7, requiring full sun and medium to dry sandy soil. Seeds of Sullivant’s milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Plant of sullivant's milkweed (Asclepias sullivantii) with pink flowers.
Sullivant’s Milkweed in a field — Asclepias sullivantii Engelm. ex A.Gray observed in United States of America by Nancy Navarre (licensed under CC0 1.0)
Plant of sullivant's milkweed (Asclepias sullivantii) in a field.
Pink Flowers of Sullivant’s Milkweed — Asclepias sullivantii Engelm. ex A.Gray observed in United States of America by samk (licensed under CC0 1.0)
Herbarium specimen of sullivant's milkweed (Asclepias sullivantii).
Herbarium Specimen — Asclepias sullivantii Engelm. ex A.Gray Collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)

14. Common Milkweed (Asclepias syriaca), a Milkweed for all Conditions

Common Milkweed (Asclepias syriaca): Common milkweed is native throughout the state (Kartesz 2015). In the wild, common milkweed is found in open areas such as fields, pastures, and roadsides, where it can receive full sun. One of the taller milkweeds, it can grow up to 6 feet tall and has flowers ranging from pink, greenish-purple, greenish-white, to white that bloom from June to August.

In your Iowa butterfly garden, common milkweed is hardy in zones 3-9 and grows in almost any exposure and soil condition, though it prefers full sun. Seeds of common milkweed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Flowers of Common Milkweed (Asclepias syriaca), a North Carolina milkweed.
Pink Flowers of Common Milkweed in McMullen House Garden — Robert Coxe, Image
Plant of common milkweed (Asclepias syriaca) with pink flowers.
Common Milkweed (Asclepias syriaca) with pink flowers — Cbaile19, CC0, via Wikimedia Commons
Common milkweed (Asclepias syriaca) with eastern tiger swallowtail.
Eastern Tiger Swallowtail Butterfly on Common Milkweed — Author Image

15. Butterfly Weed (Asclepias tuberosa), a Milkweed for all Conditions

Butterfly Weed (Asclepias tuberosa): Butterfly weed is one of the most common for butterfly gardeners on the east coast of the United States. In Iowa, subspecies interior of this species is native throughout the state (Kartesz 2015). In the wild, butterfly weed grows in open areas with full sun such as fields, roadsides, and open woods. Growing from 1 to 3 feet tall, the characteristically orange flowers bloom throughout the summer and sometimes into the autumn.

In your Iowa butterfly garden, it is hardy from zones 3-9 and grows in most conditions, but prefers full sun if possible. Seeds of butterfly weed can be purchased in the McMullen House Bed & Breakfast Garden Shop.

Orange flowers of butterfly weed (Asclepias tuberosa).
Butterfly Weed with Orange Flowers — Robert Coxe, Image
Monarch butterfly on butterfly weed (Asclepias tuberosa).
Butterfly Weed with Monarch Butterfly — Laura Perlick, U.S. Fish and Wildlife Service, Public domain, via Wikimedia Commons
Follicles of butterfly weed showing seeds.
Butterfly Weed Follicle — User:SB_Johnny, CC BY-SA 3.0, via Wikimedia Commons

16. Whorled Milkweed (Asclepias verticillata), a Milkweed for Medium to Dry Soils

Whorled Milkweed (Asclepias verticillata): Whorled milkweed is native throughout the state (Kartesz 2015). In the wild, whorled milkweed grows in open areas such as meadows and fields, where it can take advantage of full sun. Growing up to 3 feet tall, this milkweed has green to white flowers that bloom from May to September.

In your Iowa butterfly garden, whorled milkweed is hardy in zones 3-9, requires full sun to part-shade and medium to dry soil. Seeds of whorled milkweed can be purchased at the McMullen House Bed & Breakfast Garden Shop.

Close-up of white flowers of whorled milkweed (Asclepias verticillata).
White Flowers of Whorled Milkweed — Joshua Mayer (wackybadger), CC BY-SA 2.0, via Wikimedia Commons
Leaves of whorled milkweed (Asclepias verticillata).
Leaves and Stem of Whorled Milkweed (Asclepias verticillata) — Frank Mayfield (gmayfield10), CC BY-SA 2.0, via Wikimedia Commons
White flowers of whorled milkweed (Asclepias verticillata) in an open area.
Whorled Milkwed with White Flowers — Mason Brock (Masebrock), Public domain, via Wikimedia Commons

17. Green Comet Milkweed (Asclepias viridiflora), a Milkweed for Medium to Dry Soils

Green Comet Milkweed (Asclepias viridiflora): Green comet milkweed is native throughout Iowa (Kartesz 2015). In the wild, green comet milkweed grows in open areas such as meadows and field where there is full sun. Growing up to 3 feet tall, it has flowers that start out green color but age to become yellow and purple tinged. The flowers bloom from June to August.

In your Iowa butterfly garden, it is hardy in zones 3-9, requires full sun to part-shade, and medium to dry sandy soil. Seeds of green comet milkweed can be purchased at the McMullen House Bed & Breakfast Garden Shop.

Green flower cluster of green comet milkweed (Asclepias viridiflora).
Green Comet Milkweed (Asclepias viridiflora) with yellowish-green flowers — Patrick Alexander from Las Cruces, NM, CC0 1.0, via Wikimedia Commons
Plant of green comet milkweed (Asclepias viridiflora).
Green Comet Milkweed in a Field — Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, via Wikimedia Commons
Leaves of green comet milkweed (Asclepias viridiflora).
Green Comet Milkweed Leaves — Patrick Alexander from Las Cruces, NM, CC0 1.0, via Wikimedia Commons

When selecting your Iowa milkweed, be sure to make sure that it grows in your zone and habitat.

References for Iowa Milkweeds

  • Kartesz, J.T. The Biota of North America Program (BONAP). 2015. Taxonomic Data Center. Link to website. Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]
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Robert Coxe

Robert Coxe

Robert Coxe is a professional ecologist and botanist who has worked as the State Ecologist of Delaware and as an ecologist for the Western Pennsylvania Conservancy. He is also a former Past-President of the Pennsylvania Academy of Science. He currently is an innkeeper at McMullen House Bed & Breakfast LLC and a web designer and owner for Silphium Design LLC.

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