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Mickey Rathbun: Singing the praises of butterfly weed

  • Spicebush swallowtail butterfly feeding on orange milkweed flowers with soft green background Beka_C—Getty Images/iStockphoto

  • Monarch butterfly (Danaus plexippus) feeding on purple butterfly bush flowers, natural green background with copy space Leena Robinson—Getty Images/iStockphoto


Thursday, August 10, 2017

Two weeks ago, I wrote about the pros and cons of the butterfly bush (Buddleia davidii). (The con isn’t really a con, by the way. It’s just that butterfly bush provides sustenance only to butterflies and not to their caterpillars). By now, I’m pleased to report, my butterfly bushes are laden with flowers that look like lavender and purple spear tips. Butterflies and hummingbirds are regular visitors.

My butterfly weed (Asclepias tuberosa) is also in bloom, and is attracting its fair share of tipplers. Unlike butterfly bush, it has the advantage of being a host plant for monarchs. Not only do the butterflies sip its nectar, but they lay their eggs on its leaves, and the hatched larvae — i.e. caterpillars — feed on the leaves as they grow and pupate.

Butterfly weed is one of many members of the milkweed family that serve as monarch hosts. It grows wild in sunny open fields, mainly in the south, and is widely available in plant nurseries in our area. It has flat-topped clusters of upright orange flowers. Each flower has five petals that hang down, and five upright curved petals called hoods, each possessing one horn forming within the hood.

The Swedish botanist and father of modern taxonomy Carl Linnaeus named the plant after Asklepios, the Greek god of healing. This was because the plant’s root, a long, thick, pale tuber, was used to treat a wide assortment of illnesses and ailments. The root was ground or smashed and steeped boiling water to make a tea. It was used to treat pleurisy, a painful inflammatory lung disease, and was sometimes called “pleurisy root.” It has been used to combat asthma and rheumatism, as a diuretic and laxative, and for eliminating intestinal worms. It was a principle ingredient in Lydia E. Pinkham’s Vegetable Compound used in the late 1800s to treat “female problems” of menstrual cramps and menopause.

These days, Asclepias tuberosa is recognized not so much for its curative properties but for its value in supporting the embattled monarch butterfly population. Butterfly weed was named Perennial Plant of the Year for 2017 by the Perennial Plant Association because of its pollinator-friendly attributes.

The biggest threat to monarchs (and other butterflies) is the increasing destruction of their natural habitat for agriculture and development. A female monarch will only lay her eggs on milkweed, and if she can’t find milkweed, she won’t lay. Other kinds of butterflies are just as particular about the plants where they will lay eggs; the destruction of natural habitat affects all butterflies.

Roundup, which Monsanto considers the “flagship of its agricultural chemicals business,” is a major threat to butterfly habitats. Roundup is used by farmers and agribusiness to kill weeds, including milkweed (Roundup may also cause cancer in humans. The New York Times reported this week on a recent lawsuit that charged Monsanto with trying to influence scientific reports to downplay the chemical’s potential harm. But that’s another story…).

Insecticides are another leading cause of butterfly death. Certain butterflies, including cabbage butterflies, are considered pests because they eat farm crops. Farmers turn to insecticides, which are not targeted to the specific pest and also kill many kinds of butterflies and other insects. Butterflies are also susceptible to a newer form of pesticide, neonicotinoids, which put poison directly into the plant tissue.

If you have an empty sunny spot, fill it with butterfly weed. The plant is an easy keeper. It likes lots of sun, can tolerate poor quality soil and drought, and deer don’t care for it. There is a bright yellow Asclepias tuberosa named ‘Hello Yellow’ that will add even more color to your August gardens. Butterfly weed makes a lovely cut flower, if you have enough to spare.

Something to remember about butterfly weed: It is slow to break dormancy in the spring, like false indigo (Baptisia australis) and balloon flower (Platycodon grandifloras). Be sure to mark where you’ve planted it before you put your garden to bed for the winter so you don’t disturb it accidentally when you’re working in the spring garden. I have learned this lesson the hard way!

Mickey Rathbun can be reached at foxglover8@gmail.com.