July 15, 2010 13 Comments
Our guest blogger for today is Anne McCormack. I have known Anne (or known of her) for more than 25 years now, first as a long-time editor of Nature Notes, the journal of the Webster Groves Nature Study Society, and more recently on a personal basis as I, myself, have followed in her editorial footsteps. Anne is an astute naturalist whose breadth of knowledge spans not only botany but also entomology and ornithology, all of which she write about in her own blog at Gardening with Binoculars.
I planted Common Dogbane (Apocynum cannibinum) because some of my butterfly-watching friends reported numbers of juniper hairstreak butterflies on the patch of dogbane at Powder Valley Nature Center in Kirkwood. I assumed incorrectly that dogbane was a host plant for hairstreaks, and believing it to be little more than caterpillar food, I placed it in a hot, dry, narrow strip along the driveway. Ragged, caterpillar-chewed leaves wouldn’t be noticed there, and I forgot about it. After a few seasons, it was still a modest-sized clump, but the leaves were in great shape. In fact, it had grown into an attractive bush of airy, elegant lime-green foliage, wine-red stems, and tiny white flowers. It’s quite a contrast to its relative, Common Milkweed, growing next to it, which looks as if it were designed by Dr. Seuss—even before it gets chewed to bits. At this point I decided it was time to look it up and see why it had failed to support hordes of munching caterpillars. As you have already guessed, gentle reader, the Juniper Hairstreak’s host plant is juniper, not dogbane, but good old Common Dogbane is a great nectar plant. Now that Dogbane and I understand each other better, I can appreciate the amount of traffic its tiny white blooms bring in, like this Peck’s Skipper butterfly. Ants, butterflies, tiny native bees, honeybees, and this mason wasp are busy there all day long.
Along with several species of moth, it is the host plant for the Dogbane Beetle, which spends its larval stage devouring the roots and its adulthood dining on the leaves of Dogbane, and nothing but Dogbane. Dogbane Beetle can be confused with Japanese Beetle by beginners like myself, but unlike its fellow Coleopteran, Dogbane Beetle is harmless. That makes its iridescence all the more gorgeous, as shown in this wonderful photo by Courtnay Janiak. It’s a native insect that has shared a long evolutionary history with this under-appreciated native plant. American Indians valued it for its bark, which is tough but peels off in long strips. They plaited it for bowstrings and anything that called for twine; hence, its other common name, Indian Hemp. Don and Lillian Stokes, in their 2002 PBS show about bird watching, demonstrated how birds seek out the dry stems of this perennial, pulling off strips for nests in early spring. Nesting material can be hard to come by for birds in the tidy suburbs, so I don’t clean up the stems after frost. “Bane” in the name refers to the toxin cymarin in the plant’s leaves, though the plant would have to be covered in braunschweiger before my dog would be interested. Edgar Denison, in Missouri Wildflowers, translates the genus name Apocynum as “away dog.” The species name cannibinum refers to hemp. Its seedpods remind me of French green beans. These split at the end of the season, and the seeds fly away on fibers similar to milkweed seeds. Collect some and try this plant in your butterfly or native plant garden. Give it a spot where it’s easy to watch the colorful visitors.
Copyright © Anne McCormack 2010