Summer Wildflowers: Milkweed

Best known as the host plant to monarch butterflies, “showy” milkweed (Asclepias speciosa) is a very common summer wildflower in Colorado!

Photo Credit: Justin Meissen, Wikimedia Commons

Aside from milkweed’s cluster of pink flowers, its large, wide leaves are its most distinctive feature. This plant gets its name from its milky sap, which contains cardiac glycosides, making it toxic to birds and some other animals. So how is it that monarch butterflies can feed on this plant as caterpillars and pollinate it as adults?

Simply, milkweed is not toxic to monarch butterflies the way it is to some of its predators. When monarch caterpillars and adults feed on milkweed, they take in these toxins, making them poisonous to birds and other predators!

Photo Credit: Milkweed 4 Monarchs, Environment Texas, Clear Lake Conservancy

Milkweed also provides a source of nectar and pollen for other kinds of butterflies, bees, and other pollinators, although they do not have the unique relationship with the plant that monarch butterflies do.

Milkweed can also be toxic to humans and pets if ingested in certain quantities, or if introduced to the eyes; however, milkweed is a beautiful and ultimately safe plant to bring into your yard, and your local pollinators will thank you for it! Check out the Milkweed Finder by the Xerces Society to learn which native milkweed variety is best suited to your area.