By Molly Day
All the Dirt on Gardening
Each flower lasts but a single day, but we love spiderworts anyway. They bloom for several weeks, with each plant producing waves of new triangle-shaped flowers.
Tuck them near the trunks of trees and shrubs or between perennials in a flower bed where they can get a little sun and they will multiply from one year to the next. Being near the roots of larger plants not only gives them cover from too much sun, but the larger plants absorb extra moisture so the spiderworts have moist, but well-drained soil in which to grow.
Spiderworts can grow in full sunlight to full shade and will move to suit themselves. As nearby shrubs grow, spiderwort plants will pop up in other places.
Some gardeners plant spiderworts in containers to keep the plants from spreading too much throughout their gardens. It is also very easy to pull up and thin out the tiny plants during early spring garden cleanup to control their inclination to naturalize.
If you want to try them in full sun, be sure to water them regularly to prevent scorching. Half a day of sun seems to work best in our area.
Each little flower is a perfect three-petaled jewel-tone color spot on top of a stem that can be 6 to 36 inches tall. The stems are soft, and the leaves resemble lily leaves, giving them their other common name, spider lily. They are cold hardy in USDA zones 4 through 11, and are drought and wet tolerant, deer resistant and easy to grow. They also tolerate black walnut trees.
The most common spiderwort is the American native, tradescantia virginiana. Woodland spiderwort, tradescantia ernestaniana, Ernest's spiderwort or red cloud are native to Oklahoma, Alabama, Arkansas and Missouri. It is less aggressive than Ohio spiderwort. Plants and seeds are available from Easy Wildflowers in Missouri. (www.easywildflowers.com). Tharp’s spiderwort, tradescantia tharpii, is native from Texas to Kansas.
Plant woodland spiderwort with other native woodland wildflowers such as columbine, green dragon, American spikenard, Jack-in-the-pulpit, goat's beard, wild ginger, wild geranium, Virginia bluebells, woodland phlox, Jacob's ladder, ferns and other shade flowers.
When the flowers fade, cut the plants all the way down. New growth will appear, and a second bloom season will come when the weather cools in the fall. Divide the clumps early in the fall or when the leaves emerge in the spring.
If they go to seed and seedlings come up near the parent plants, they can be lifted and planted elsewhere.
The flowers attract butterflies from May to July, and the seed heads attract gold finches. At the end of the bloom season, the fading stems and leaves turn yellow, so spiderworts are usually planted in a natural area or where summer blooming flowers can hide them. Spider lilies self-clean, so they do not have to be deadheaded.
In addition to the natives, there are more than 60 tradescantia species.
Tradescantia pallida, commonly called purple queen, purple heart and purple spiderwort, is primarily grown for its deep purple leaves because the tiny tri-corner pink blooms can barely be seen in a flower bed.
Tradescantia fluminensis, commonly called creeping Christian or wandering Jew, is hardy in zones 7 through 9 and is often grown as a houseplant. A close relative, tradescantia pallida purpurea, commonly called purple wandering Jew, is also a great shade plant to grow as annuals under trees.
Tradescantia andersoniana osprey is named for the bird of that name. It has white flowers with blue stamen filaments (available from www.forestfarm.com). Other white flowering varieties include Bilberry Ice, Snowcap, Iris Prichard and Innocence (see www.marysplantfarm.com).
Spiderwort plants are not only edible and medicinal; they are also used by scientists to detect radiation fallout (http://bit.ly/dNX8DH).