~ Plant Highlight ~
White wingstem (Verbesina virginica), a.k.a. white crownbeard, a.k.a. frostweed, a.k.a. frostflower, is a native, fall-blooming, perennial wildflower. White wingstem blooms from Aug. through Oct. in Kentucky, and grows in medium to slightly moist, open woodlands and fields. It can reach over 5 feet tall.
Honey bees, native bees, and butterflies love both varieties of wingstem. Because it blooms so late in the season, white wingstem can provide a valuable last source of nectar and pollen before the killing frosts start. White wingstem is also a host plant for the silvery checkerspot (Chlosyne nycteis) caterpillar and the summer azure caterpillar (Celastrina neglecta).
White wingstem gets its common name of “wingstem” because it has long, leafy outgrowths running up and down its stem. The common names of “frostweed” or “frostflower” come from a characteristic that is observed on the first really cold nights of the year.
When the air temperature dips below freezing but the ground and plants haven’t frozen yet, frost flowers can form along the stem of white wingstem. Frost flowers aren’t flowers and aren’t made of frost. They occur when the sap in certain plants, such as white wingstem, starts to freeze. Since liquids expand as they freeze, the freezing sap splits the stem. The sap slowly leaks out the stem, freezing instantly as it hits the cold air and forming ribbons of ice known as frost flowers.
White wingstem is a good, late blooming, native plant to grow in pollinator gardens, but it can be aggressive in small settings. They are best grown in larger, less formal garden settings where their tendency to spread won’t create problems.
Shannon Trimboli is a beekeeper, farmer, wildlife biologist, and author. She owns Grassy Roads Farm and Busy Bee Nursery & Consulting. Busy Bee Nursery & Consulting specializes in plants and habitat consulting services for honey bees, native pollinators, and wildlife conservation. In 2018, her first book, Plants Honey Bees Use in the Ohio and Tennessee Valleys, was published. Shannon also writes a weekly blog called Kentucky Pollinators and Backyard Wildlife. The blog features profiles of pollinators and wildlife, tips for attracting pollinators and wildlife, highlights of different plants for pollinators and wildlife, and life on the farm and nursery. You can sign up to have her blog emailed to you.