Growing Milkweed to Help Monarch Butterflies

When I tore up a patch of lawn near my driveway for a native plant garden, I chose to make room for some butterfly weed (Aesclepias tuberosa). I'm glad I did.

My Aesclepias tuberosa has thrived in my little wildlife garden. The plants, which grew to be 2- to 4-feet tall, produce large showy flowers in late June in suburban Chicago. The plants' large orange flowers attract loads of butterflies, which is how butterfly weed got its nickname.

The flowers are followed by large green pods. Inside the pods are dozens or hundreds of brown seeds, each attached to a fuzzy tail. When mature, the pods burst open and the seeds are carried by wind to another location. Aesclepias tuberosa self-sows readily and is often grown from seed.

When it's not blooming, Aesclepias tuberosa has large broad leaves that provide food essential for monarch butterfly caterpillars. Monarchs, whose populations are declining, lay their eggs on butterfly weed, the only food their caterpillars will eat. Without milkweeds, the monarch butterflies cannot reproduce. I saw the first caterpillars on my butterfly weed plants only a few months after I first planted them in my yard.

Unlike other milkweeds, the sap of Aesclepias tuberosa is clear, not milky. The plant also contains smaller amounts of cardiotoxic glycosides, which are found in other types of milkweeds. When I was a child, the camp counselors cooked immature milkweed pods for us. They tasted like green beans. Because of the cardiotoxic (poisonous) compounds present in small amounts, most experts now do NOT recommend eating butterfly weed seed pods.

Aesclepias tuberosa is a perennial, returning every year. Like many other plants found in prairies, butterfly weed has a deep tap root.

Aesclepias tuberosa can be grown from seeds or transplants. Transplants, which are most often available in the spring, can also be planted in the fall. Aesclepias tuberosa seeds are best planted outdoors in the fall. That's because many native plants require a period of chilling (winter) before they can germinate.

Aesclepias tuberosa is native to much of North America. Butterfly weed grows from New York to Minnesota, and has been found as far south as Florida. Because Aesclepias tuberosa requires full sun, it is often found in open areas. Generally light, well-drained soil is recommended. The plants will, however, grow in moist areas such as on the banks of streams.

Native Americans found medicinal uses for Aesclepias tuberosa in treating ailments such as asthma and bronchitis.

Aesclepias tuberosa is usually found at native plant sales, such as those conducted by county park districts and native plant societies. Seeds of Aesclepias tuberosa be found online from vendors such as Prairie Nursery or Prairie Moon Nursery. Young plants may also be sold in the spring at well-stocked garden centers.