Monarchs and Milkweed in the Garden

There has been a lot of talk in recent years about Monarch butterflies, and I wanted to share information about plants you can buy at Cape Shore Gardens that can help the Monarch’s survivability while adding biodiversity to your yard. Milkweed (Asclepias sp.) is the sole host plant for the Monarch butterfly, and to put simply, the Monarch life cycle: the butterfly lays the egg on a milkweed species; the egg hatches into larvae (caterpillar); the caterpillar, after getting plump from eating the only plant it hosts from (the milkweed plant), enters the pupa stage (the chrysalis); and then it turns into a butterfly. The Monarch butterfly population has decreased significantly over the years, due in particular to agricultural intensification, especially with soy and corn fields, urban development and intensive vegetative roadside management. By removing populations of milkweed, their food essentially is taken away from them and caterpillars starve.
Milkweed in its own right is a great perennial to plant in the garden for color, form and biodiversity. It is not only a host plant for Monarch butterflies, but also an important plant for pollinators such as bees, wasps and other species of butterflies for their effectiveness of transferring pollinia.
Cape Shore Gardens will be carrying four different species of Asclepias (the milkweeds) this year ranging from yellow, orange, pink and white, requiring various cultural conditions. Butterfly weed (Asclepias tuberosa) blooms bright orange mid-summer, freely self-seeding through wind dispersal in late summer into fall. It is drought tolerant once established, and more commonly available and planted throughout our region for Monarchs. Be sure to check out the golden-yellow blooming variety, ‘Halo Yellow.’ Common milkweed (Asclepias syriaca) is also a tough, drought tolerant perennial with pink blooms at three feet high. Proper planning is essential when placing this plant, as it spreads vigorously by rhizomes and can form colonies quickly!
Horsetail milkweed or whorled milkweed (Asclepias verticilata) has fine textured foliage, reminiscent of thread-leaf coreopsis with white blooms mid-summer. Despite its delicate appearance, the horsetail milkweed can handle tough, infertile soils. In optimal gardening conditions, it can spread. For the low spots in the garden that never seem to fully dry out, swamp milkweed (Asclepias incarnata) is the answer! This pink summer bloomer reaches close to five feet, and while tolerant of wet soils, it will also enjoy average, well-drained soil.
As large populations of Asclepias are eliminated, it’s important that we take the steps to add what we can to our own gardens. It is not only for conservation of Monarch butterflies, but also for Asclepias species that are part of this region’s ecology and biodiversity. Stop by or call Cape Shore Gardens if you are interested in knowing more or purchasing milkweed plants!
Cape Shore Gardens is located at 1028 Rt. 9 S., Cape May Court House. For more information, call (609) 465-5161.
Written by Lauren Popper, horticulturist at Cape Shore Gardens and graduate of Temple University’s School of Environmental Design.