Butterfly Weed follicles have a smooth surface unlike the warty Common Milkweed. Photo: Dr. John Hilty, Illinois Wildflowers
Butterfly Weed, Asclepias tuberosa
Butterfly Weed, which blooms in mid-late June might be considered a strange native to write about in May but forgive me, I’m going with the orange theme here… Plus a lot of you have bought this plant in spring native plant sales!
If you don’t know Butterfly Weed, once you see it in flower you will want it for your garden. Its brilliant orange flower clusters are a bright focal point in the full sun of early to mid-summer’s heat. In fact Butterfly Weed is known for its tolerance to hot dry weather.
At 1-2 ½ feet tall, this plant matures at a nice height for a garden. In the wild it is typically found in acidic soils that are sandy or rocky such as sandy savannas and hill prairies, abandoned sandy fields, rocky open woodlands and sandy embankments. It is also tolerant of soils that contain loam or clay but they must be well-drained. These soil preferences sometimes make it difficult to successfully grow this plant in a garden. In contrast I have seen a number of plants growing and blooming successfully in the median strip of Rte. 23 between Ann Arbor and Lansing MI. A challenging location to be sure!
Butterfly Weed, or Butterfly Milkweed as it is also called, is the only milkweed with orange flowers and the only species that does not produce milky sap although this character does not seem to make it any more attractive to nibbling animals such as bunnies and deer.
Each plant produces a hefty taproot that can extend to several feet below the surface. Young plants grow from a single stem but older plants will tiller and develop multiple upright stems at the base that widen each individual plant to about 1 ½ to 2 feet as it matures. Leaves are alternate, narrow, and oblong 2 ½ - 3 ½ inches long along the stem. Their dark green color is a nice contrast to the orange flower clusters or more accurately called umbels.
Flower color will vary on each plant from deep orange to a yellow orange. To see a full range visit the Lady Bird Johnson Wildflower Center where their photo library includes 125 images! Each umbel is made up of 8-25 of milkweed’s unique flowers that produce nectar and pollen but, unlike common milkweed, are not particularly fragrant. Seed pods that develop from fertilized flowers (more accurately called follicles), are smooth and covered with short hairs.
This milkweed species supports a number of pollinators and other native insects. Monarch butterflies of course, are dependent upon Asclepias as the food source for their larvae as are the larvae of the Unexpected Cycnic Moth. Flower nectar attracts Monarchs, honeybees, a wide range of native bees, other butterflies including Fritillaries and Swallowtails and the Ruby-throated Hummingbird.
With milkweeds also come a variety insects that feed on the plant. These include both the Large and Small Milkweed Bugs, and the Blackened Milkweed Beetle.