Description & Overview
One of these milkweeds is not like the others. And its name is Poke Milkweed! The white-lavender flowers are still arranged in an umbel, though it is a little more loosely packed, containing fewer flowers per umbel than other species. That said, each flower produces copious amounts of nectar and releases a very noticeable sweet fragrance. The leaves are largest when the plant is sited in shade, reaching up to 10 inches long. Thin, tapered seed pods release the seeds in the fall, each attached to long silky hairs, and are carried away by the wind.
Many a hiker has been surprised by Poke Milkweed as it is often found along woodland edges in part shade. This is quite different from other milkweed species, which can differ in moisture level needs, but without question, do their best in full sun locations. Poke Milkweed likes the forest with dappled shade and loamy soils and shelter from the worst of the wind. It is also found in forest clearings in sandy or even rocky soil, as long as it is organically rich.
It has been noted that Common Milkweed and Poke Milkweed have hybridized in the wild. Though this is possible, it would take a specific set of circumstances as Common Milkweed is found growing out in the open in full sun and poor, disturbed soils so it is less likely that they would be neighbors. It is worth noting though, that over time if you choose to plant them both in your landscape there is a chance that you could end up with something that is a little bit of both.
Butterfly Garden/Pollinator Garden: It is interesting to note that Monarchs seem to prefer Poke Milkweed over others. This may be due to the stronger scent of the flowers. Regardless of exactly how much they like the flowers, it is certainly safe to say that Monarchs flock to them. This is an excellent Milkweed for a garden. If your home is in a shady woodland setting and thought you would never be able to give milkweed a go then, HA! This is it!
Naturalization: It is a native that produces copious amounts of nectar along with pollen. Bees love it as do many species of butterflies. Add this species to a restoration/naturalization project for its benefit to wildlife as well as a little diversity.
Poke Milkweed is a pollinator magnet. Native bees and bumblebees flock to it. The Great Spangled Fritillary butterfly, who prefers the same woodland habitat, drinks the nectar. As all in the genus Asclepias, it is the larval host to the Monarch Butterfly, the adults laying eggs on leaves (check underneath!) and also feeding on the nectar.
The mechanics involved in the pollination of milkweed flowers and their reliance on heavy-bodied insects (butterflies, bumblebees) to trip the mechanism is truly fascinating. The insect is tempted to drink fragrant nectar from slippery structures on the milkweed flower called a hood. The flowers are designed so that the insect’s leg will slip down into a crack, which happens to hold the pollen sac. Larger insects are strong enough to pull their leg, along with the pollen sac, out of this crack to bring it to the next flower at which point the pollinator’s leg slips into the crack and drops off the pollen sac while pulling its foot back out to complete pollination. Interestingly, smaller insects such as honeybees may be large enough to get their foot stuck, but too small to get it out and can get stuck in the flower, losing a limb while trying to escape, or dying on-site. One might wonder what makes it worthwhile to risk literal life and limb to visit a milkweed flower but it is safe to assume it is likely due to the high volume of nectar they produce. It is also worth asking if the decline in milkweed is not just due to dwindling habitat but also due to the decline of the bumblebees, and others, who are the only ones capable of pollinating it! You can learn about the mechanics of milkweed pollination in detail with pictures and the correct biological terminology at Milkweed Pollination Biology (PDF by nrcs.usda.gov). At the very least you will appreciate how complex it is and have a little more wonder at the natural world in your life.
Several beetles feed specifically on the stems and leaves of milkweeds such as the Swamp Milkweed Leaf Beetle, Milkweed Longhorn, Red Milkweed Beetle, and the Milkweed Stem Weevil.
Milkweed contains a toxic, white, milky sap that famously imparts its toxicity to the Monarch caterpillars as they feed on it, giving them a defense against predators. This milky substance is not only toxic but also very bitter and succeeds in keeping the rabbits and deer away, though there are accounts of the occasional nibble or more.
If spreading is not desired, then collect the pods in the fall before they open to prevent the seeds from scattering.
The plant may be cut down at the end of the season when it begins to look worse for wear; however, waiting until spring to clean up perennials may be more friendly to fall and winter wildlife.
If choosing a full sun site use a layer of bark mulch about one to three inches deep to keep the soil cool and moist.
Black Walnut Tolerant: No
Deer Resistant: Yes
Rabbit Resistant: Yes
Aphids will likely inhabit the plant – this is normal, natural, and part of the prairie ecosystem. There is no need for removal or pesticides: this will affect other eggs that have been laid on the plant by beneficial pollinators.
The milky white sap that is apparent when a leaf is broken contains toxic cardiac glycosides and resinoids which prevent mammals from foraging on it. If it is eaten in large enough quantities it can cause vomiting, spasms, and general weakness.
The leaves of Poke Milkweed resemble those of the genus Phytolacca, whose common name is Pokeweed. Poke Milkweed was once known as A. phytolaccoides which translates to “Phytolacca-like.”
The milkweed genus Asclepias is named after the Greek god of healing, Asklepios. Many parts of several species of Asclepias were eaten or used medicinally by Native Americans. Considering the plant is quite toxic we will not go into detail here. The fibers found in the seed pods were used to make fish nets and ropes.
American Elderberry, Common Witchhazel, Bottlebrush Buckeye, Spikenard, Zig Zag Goldenrod, and Virginia Bluebells could all be found in the understory along with Poke Milkweed in the dappled shade of the canopy.