In recent years milkweed has received much attention as habitat for dwindling populations of monarch butterflies. Most of the more than 100 species in the Americas are tropical, but one species in particular is a staple of monarchs in the North: Common Milkweed (Asclepias syriaca).
My backyard milkweed project started in 2015 with a few transplants from a nonproductive, roadside location. Establishment was slow, but they’re now flourishing. Vegetative reproduction by root sprouts has created a colony of about 30 stems and the large, fragrant flower clusters are insect magnets (according to the US Forest Service, over 450 insects are known to feed on some part of the plant, including flower nectar). I focused on the Lepidoptera, attempting to document the variety of butterflies and moths that benefit from flowering milkweed. Multiple benefits from a single management action is a best-case scenario. The value added from a colony of milkweed is much greater than monarch habitat.
I’ve observed 9 or 10 species of butterflies and moths thus far, as well as countless bees, flies and other insects. This is a sample!
Several years ago I discovered a group of milkweed plants growing at the edge of the property. They were in the shade of a 60-foot-tall Norway spruce and lacked the vigor and floral production of open-grown plants. Mindful of the decline of Monarch butterflies and their habitats, I transplanted about 15 plants to better sites in full sun. This was done in the spring of 2015 and 2016.
Most plants survived the stress of transplanting but they didn’t become fully acclimated and established until this year. I’m now pleasantly surprised with the results, and plan to continue the project. The new colonies are producing root sprouts as well as flowers, and the response of nectaring insects was immediate.
Here is a small sample of milkweed visitors last week – and several plants have not reached full bloom yet! This is a wildlife manager’s dream scenario: one action, with multiple benefits.
Banded Hairstreak butterfly (milkweed flowers are a preferred food source)
Virginia Ctenucha moth
Tiger Swallowtail butterfly
Given the insect activity, I wasn’t surprised to find a common 8-legged predator lurking in the flower clusters: the Flower Crab Spider (I had to gently lift the flower cluster and shoot one-handed to get the image).