Whorled Milkweed

asclepias verticillata

Whorled Milkweed (Asclepias verticillata) is an elegant, slender perennial wildflower native to eastern and central North America. Unlike its broader-leafed milkweed relatives, this species features thin, needle-like leaves arranged in delicate whorls around a single, erect stem. It stands out in late summer with its clusters of small, fragrant white-to-greenish-white flowers. This plant plays a vital ecological role, acting as a crucial host plant for monarch caterpillars and a magnet for various native pollinators, while also producing a toxic sap that deters generalist herbivores. To easily track and identify Whorled Milkweed on your next adventure, download the Snappit app.

Habitat: Found in dry, open woodlands, prairies, pastures, and along roadsides, often thriving in poor, sandy, or rocky soils.

Appearance

This herbaceous perennial typically grows to a height of 30 to 90 cm, with narrow, linear leaves measuring 5 to 8 cm long that grow in whorls of 3 to 6 around the stem. In mid-to-late summer, small flat-topped clusters of star-shaped, greenish-white to cream-colored flowers bloom from the upper leaf axils. Each individual flower is roughly 6 mm wide, exhibiting five reflexed petals and a central crown. Following pollination, it produces slender, upright seed pods that dry and split to release fluffy, wind-dispersed seeds.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderGentianalesFamilyApocynaceaeGenusAsclepias

Whorled Milkweed

Interesting facts

It is one of the latest-blooming milkweeds, making it an essential late-season nectar source for migrating Monarch butterflies and native bees.

The seeds have silky hairs called floss, which during World War II were collected by school children to stuff military life jackets when traditional materials were scarce.

Whorled Milkweed is one of the most toxic milkweed species to livestock, particularly sheep and horses, earning it a reputation as a rangeland weed.

Special abilities

Produces toxic cardenolides in its milky sap, which deter herbivores and are sequestered by monarch larvae for their own defense.

Utilizes a deep, fibrous root system to access deep water reserves, helping it survive intense droughts and wildfires.

Equips its seeds with fine, silky hairs that catch wind currents, allowing them to disperse over long distances to colonize new open sites.

Measurements & details

Length: 30-90 cm
Lifespan: 3-10 years

Diet & Feeding

As a photosynthetic plant, Whorled Milkweed synthesizes its own organic compounds using sunlight, water, carbon dioxide, and mineral nutrients from the soil.

Primary Foods

Sunlight
Water
Carbon Dioxide
Soil Minerals

Ecological connections

eaten by

Monarch Butterfly

Danaus plexippus

Larvae feed exclusively on the foliage of milkweeds, gaining chemical protection from predators.

mutualism

Honey Bee

Apis mellifera

Adult bees visit the flowers for nectar, successfully pollinating the plant in the process.

Traits

No trait badges are assigned for this object yet.

Also known as

No aliases listed yet.

Collections

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Whorled Milkweed?

The easiest way to identify Whorled Milkweed is to use the Snappit nature identifier app.

How long is Whorled Milkweed?

30-90 cm

How long does Whorled Milkweed live?

3-10 years

What does Whorled Milkweed eat?

As a photosynthetic plant, Whorled Milkweed synthesizes its own organic compounds using sunlight, water, carbon dioxide, and mineral nutrients from the soil.

Where is Whorled Milkweed usually found?

Found in dry, open woodlands, prairies, pastures, and along roadsides, often thriving in poor, sandy, or rocky soils.