Description & Overview

Purple Milkweed is a very rare native plant in Wisconsin and is listed as Endangered by the Wisconsin DNR. This erect perennial grows up to 3′ tall with a single stem covered in fine hairs. The leaves are a green-yellow and are furled a bit toward the mid-vein of the leaf. Fragrant, red-purple flowers set this Milkweed apart from others, blooming from late spring to mid-summer in a cluster at the top of the stem. As blooms fade, smooth, upright seed pods that contain many seeds will replace them.

Core Characteristics

Category: Perennial

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 4

Mature Height: 18-36 inches

Mature Spread: 12-24 inches

Growth Rate: Moderate

Growth Form: Erect

Light Requirements: Full Sun to Partial Shade

Site Requirements: Mesic-moist soils

Flower: Red-purple, 5-parted, ½-2/3" tall

Bloom Period: June-July

Foliage: Green-yellow, pubescent, up to 6" long, curled toward the mid-vein

Fall Color: None

Urban Approved: Yes

Fruit Notes: Seed pods contain many seeds attached to a fluffy pappus, erect, smooth

Suggested Uses

Purple Milkweed is typically found in part-shaded habitats in mesic conditions, such as along lot lines and in thickets. It is not particularly fussy. Typical of other plants found along woodland edges, it appreciates some shade in the daytime.

In the landscape, Purple Milkweed can be added as an understory planting, or along the border of your native or wildflower garden. The deep red-purple flowers make a nice accent when paired with ornamental grasses or coneflowers.

As a host plant to a variety of insects, it is a lovely addition to a butterfly or pollinator garden. The bitter foliage will also keep other non-pollinating animals at bay. Consider planting Purple Milkweed along the moist edges of a rain garden.

Purple Milkweed spreads via seeds but also by rhizomes. Although less aggressive than Common Milkweed (Asclepias syriaca), this habit can be useful when naturalizing an area, or when making a visual impact with massed plantings.

Purple Milkweed is a very rare native plant in Wisconsin and is listed as Endangered by the Wisconsin DNR. This erect perennial grows up to 3' tall wi…

Wildlife Value

Purple Milkweed has all of the same benefits to pollinators as others in the Asclepias genus. It is the host plant to the Monarch butterfly (Danaus plexippus), Milkweed Tussock Moth (Euchaetes egle), Common Milkweed Bug (Lygaeus kalmii), Red Milkweed Beetle (Tetraopes tetrophthalmus), Large Milkweed Bug (Oncopeltus fasciatus), Swamp Milkweed Leaf Beetle (Labidomera clivicollis), and Unexpected Cycnia Moth (Cycnia inopinatus).

All of these insects feed on Milkweed during their development, resulting in an orange-red aposematic coloring that warns birds that they are not palatable. When these insects feed on the plant, their body acquires toxic compounds like alkaloids that the plant contains. These compounds accumulate in the insects’ bodies and will harm what may try to eat them. Or, at the very least, not taste good.

Other visitors seeking nectar include the Edward’s Hairstreak (Satyrium edwardsii), Coral Hairstreak (Satyrium titus), Regal Fritillary (Speyeria idalia), Red Admiral (Vanessa atalanta), Painted Lady (Vanessa cardui), Mourning Cloak (Nymphalis antiopa), Common Buckeye (Junonia coenia), Eastern Tiger Swallowtail (Papilio glaucus), Eight-spotted Forester Moth (Alypia octomaculata), Hummingbird Clearwing Moth (Hemaris thysbe), Great Spangled Fritillary (Speyeria cybele), Sulphur butterflies (Colias spp.), Western honeybees (Apis mellifera), Leafcutter bees (Megachile spp.), Green Sweat bees (Augochlora spp.), Small Carpenter bees (Ceratina spp.), Small Resin bees (Heriades spp.), Sweat bees (Lasioglossum spp.), Thread-waisted wasps (Prionyx spp.), Cuckoo bees (Coelioxys spp.), Soldier bees (Chauliognathus spp.), Banded Long-horned beetles (Typocerus spp.), Long-horned beetles (Euderces spp., Trigonarthris spp.), Bumble bees (Bombus spp.), Yellow-faced bees (Hyaleus spp.), and Ruby-throated Hummingbirds.

Mammalian herbivores rarely consume this plant because of the bitter-tasting, toxic foliage.

Maintenance Tips

Low-maintenance, plants will need supplemental watering during times of drought.

Pests/Problems

Black Walnut Tolerant: Yes
Deer Resistant: Yes
Rabbit Resistant: Yes

Milkweeds are prone to aphids. This is normal. In fact, quite a few insects will eat the leaves, this is their contribution to our ecosystem. Embrace it!

This species has a long taproot, making transplanting difficult.

Leaf Lore

The genus Asclepias is named after the Greek god of healing, Asklepios, the originator of the staff and serpent commonly associated with medicine today. The specific epithet purpurascens means “purple.”

Purple Milkweed will hybridize with Common Milkweed (Asclepias syriaca).

Many Indigenous peoples used Milkweed for medicinal and practical reasons. The Chippewa ate Milkweed to increase their appetite, to aid in milk production, and applied the roots to whistles to call deer. The Ojibwa ate the young shoots and flower buds and used the fresh flower and shoot tips to thicken meat soups. The ‘milk’ of Milkweed was used as a treatment for warts, bee stings, and cuts by the Iroquois.

Companion Plants

Associated native species that work well in combination with Purple Milkweed include:

beth delain1 avatar

Written by Beth DeLain