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A Comprehensive Guide to Green Comet Milkweed (Asclepias viridiflora)

Green Comet Milkweed (Asclepias viridiflora) is a herbaceous perennial that is found in the mid-west and eastern United States and in Canada. This milkweed is a host plant to the Monarch Butterfly and a nectar plant to others. It can grow up to 3 feet tall and has linear-shaped leaves. The green flowers that become yellowish to purple-tinged with age, bloom from June to August and is hardy in zones 3-9. The seeds for this plant can be purchased in the McMullen House Bed & Breakfast Garden Shop from the link below.

Taxonomy and Naming of Green Comet Milkweed (Asclepias viridiflora)

Herbarium specimen of green comet milkweed (Asclepias viridiflora).
Herbarium Specimen — Asclepias viridiflora Raf. Collected in United States of America by The New York Botanical Garden (licensed under CC BY 4.0)


Green Comet Milkweed (Asclepias viridiflora) was named and described by Constantine Samuel Rafinesque, an French botanist, in Flora Caroliniana (1788). While the original specimen of the description is unknown, the neotype is a specimen collected in 1939 from near Georgetown, South Carolina. This species has kept the same name since. This plant is a member of the Dogbane Family (Apocynaceae).

Synonyms (from Biota of North America Program –

  • Acerates viridiflora (Raf.) Pursh ex Eat.
  • Acerates viridiflora var. ivesii Britt.
  • Acerates viridiflora var. linearis Gray
  • Asclepias viridiflora var. lanceolata Torr.
  • Asclepias viridiflora var. linearis (Gray) Fern.

Meaning of the Scientific and Common Names

Scientific Name

The genus name, Asclepias, is named for the Greek god of healing, Asklepios (Flora of Wisconsin). The genus name, viridiflora, is Latin for green-flowered.

Common Name and Alternative Names

The common name of this plant refers to the round structure of the flower and the color. Another common name, wand milkweed, similarly points to the shape of the flower. Other common names such as green milkweed, short green milkweed, and green-flowered milkweed are in reference to the flower color.

Physical Description

Close-up of flowers of green comet milkweed (Asclepias viridiflora).
Flowers of Green Comet Milkweed — Barnes Dr Thomas G, U.S. Fish and Wildlife Service, Public domain, via Wikimedia Commons


  • Plant Type: Herbaceous perennial
  • Height: 1 to 3 feet
  • Leaves: opposite, simple, entire, clasping leaves that are 6 inches in length and 1-3 inches in width.
  • Stem: Green to purple with pubescence
  • Flower color: green when young, but becoming yellow-green to purple-green with age.
  • Blooming period: July to August
  • Fruiting type and period: follicle that matures in the fall

Range of Green Comet Milkweed (Asclepias viridiflora) in the United States and Canada

Range map of green comet milkweed (Asclepias viridiflora) in the United States and Canada.
Range Map Credit: Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. ( 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)].

This species is native to most of the United States and southern and middle Canada except for the western United States. Green comet milkweed is rare in a number of states including Florida, Arizona, New York, Connecticut, Delaware and the provinces of Alberta, Ontario, and Saskatchewan.


Prairie habitat in the state of Ohio.
Prairie Habitat — Sixflashphoto, CC BY-SA 4.0, via Wikimedia Commons

This milkweed is found growing on open areas such as fields, dunes, and prairies, shaded roadsides, forest borders, and railroads. It can be found on serpentine and calcareous soils and is generally in need of disturbance to keep its habitat open (New York Natural Heritage Program), however, the North Carolina Extension Service states that it prefers quality habitats.

Hosted Insects

Purple coneflower (Echinacea purpurea) with Monarch butterfly.
Monarch on a Purple Coneflower — Robert Coxe, Image

This milkweed, like a lot of milkweeds, is a host to the Monarch Butterfly (Danaus plexippus). It is also a host to the Queen Butterfly (Danaus gilippus).

Other Supported Wildlife

Close-up of yellow flowers of canada goldenrod (Solidago canadensis) wiht a bee.
Bumblebee on Goldenrod — AnRo0002, CC0 1.0, via Wikimedia Commons

This milkweed, again like a lot of other milkweeds, is a nectar source to other insect species, including bees and other butterflies.

Frequently Asked Questions

Is this species poisonous?

This plant, as are all milkweeds, is considered to be poisonous because of the presence of cardiac cardenolides in the milky sap.

What other species are similar to this plant?

Green Comet Milkweed, in general, can be distinguished from other milkweeds by the nodding green umbels, but it is similar to Mead’s Milkweed (Asclepias meadii) and the Tall Green Milkweed (Asclepias hirtella) – (Illinois Wildflowers). It is also similar to Oval-leaf Milkweed, but green comet milkweed has more flowers – Michigan Flora and is the only milkweed that lacks the characteristic “horns.”

Showy milkweed (Asclepias speciosa) can also appear like this species in that they both have broad leaves, however the showy milkweed has pink to purple flowers (Vanderhorst 1998).

Does this plant have any human uses?

This species has been used by Native Americans for a number of medicinal uses including skin diseases, eye disorders, gastrointestinal problems. It has also been used as food source for soups and spices (North American Ethnobotany Database).

Gardening with Green Comet Milkweed (Asclepias viridiflora)

Add Green Comet Milkweed to Your Garden

The link below takes you to our product page where we get a small commission from your purchase at no additional cost to you.

Green flower cluster of green comet milkweed (Asclepias viridiflora).
Patrick Alexander from Las Cruces, NM, CC0 1.0, via Wikimedia Commons


This species is hardy in zones 3-9. If your garden is within these zones and you have the right soil and moisture conditions, you can likely grow it even if you are not in the native range. The hosted insects for this species, the monarch butterfly (Danaus plexippus) and the Queen butterfly (Danaus gilippus) are wide ranging and are likely to be in your area. However, they may not be if out of the native range.

Optimal Conditions

This milkweed prefers open areas that have full sun or partial shade and mesic to dry sandy soil. The long horned beetle (NC Extension Gardener) has been noted as a possible problem for this plant.


  • Vanderhorst, James, Bonnie L. Heidel, et al. 1998. Botanical and Vegetation Survey of Carter County, Montana, Bureau of Land Management-administered lands. Montana Natural Heritage Program.
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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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