Железистая вернония: 25 видов астр, цветущих в Южной Каролине и привлекающих монархов

One sign of autumn on the horizon is when clusters of hairy purple flowers of ironweed start to bloom in August. At total of 25 species of this clump-forming herbaceous perennial in the Aster family are native to North America. Seven of those are native to South Carolina: V. acaulis, stemless ironweed; V. augustifolia, narrow-leaf ironweed; V. georgiana, Georgia ironweed; V. gigantea, giant ironweed; V. glauca, Appalachian ironweed; V. noveboracensis, New York ironweed; and V. pulchella, pretty ironweed. The genus name, Vernonia, honors William Vernon (c.1616-1711), British botanist and entomologist at Cambridge University who collected specimens in the mid-Atlantic in 1698. The common name, ironweed, is thought to refer to the tough sturdy stems and the overall hardiness of the genus, or perhaps the rusty color of the maturing seedheads. Ironweeds are hardy in USDA zones 4-9. They prefer full sun and rich moist soils with a pH of 6.5. Plants are often found in the wild on the edges of river-bottom forests, glades, wet meadows, and streams as well as along roadsides. While preferring sun and moisture, ironweeds can tolerate partial shade and drought conditions, too. Like milkweeds, ironweeds are bitter to taste, so mammals like cattle, deer, and rabbits avoid browsing. Ironweeds can be grown in a cottage garden, rain garden, wildflower garden, rock garden, native plant garden, prairie restoration, and pollinator garden. They pair well with autumn blooming goldenrods, obedient plants, and swamp sunflowers. Many ironweed species grow very tall. Giant ironweed can reach 12-15 feet. New York ironweed can grow four to eight-feet tall. A newer cultivar has been bred for a more compact mounding habit, V. lettermannii ‘Iron Butterfly,’ reaching two to three-feet tall. Ironweeds purple flowers are irresistible to pollinators, including long-tongued bees; beetles; butterflies, like swallowtails and monarch; flies; skippers; moths; and hummingbirds. Ironweed is the host plant for the American lady butterfly, ironweed borer moth, and parthenice tiger moth. Ironwood nectar is an important fuel food for the eastern population of monarchs during fall migration to Mexico. I plant New York ironweed and giant ironweed in monarch waystations and in bird gardens. New York ironweed and giant ironweed seeds bring a variety of birds, including American goldfinches, chickadees, finches, juncos, and sparrows. Insectivorous birds also visit ironweed during fall for the flying insects it brings. Ecologists recommend leaving the stems on ironweed during the winter for cavity-nesting bees, wasps, and other insect larvae and pupae to overwinter safely. Wait until early spring, February or March, to cut back stems. Recommended seed sources for ironweed are Ernst and Everwilde. Ironweed seeds require cold, moist stratification to break dormancy and achieve the best germination rates. For plants, check your local S.C. native plant society and Midland garden centers. For a 2025 scientific report on the three-year trial of ironweed species, visit Mr. Cuba Center at mtcubacenter.org/trials/vernonia.