With knee-high grassy leaves and bright blooms of blue, purple, pink, or white, spiderwort is an attractive and versatile perennial. For maximum impact, plant groupings of spiderwort in informal borders, cottage gardens, or woodland gardens. It also makes a nice addition to containers.
Spiderwort blooms are similar to daylilies in that individual flowers open in the morning and close in the afternoon or evening. There are about 20 buds on each stem, however, and they don?t all open on the same day.
A native wildflower in the transition zone, spiderwort begins blooming in late spring or early summer. Cut it back hard after its first flush of blooms to encourage fresh leaves, more flowers, and a tighter form. As long as you keep the soil moist, spiderwort will continue blooming right through to fall.
Spiderwort thrives in full sun to light shade. It will produce more blooms in full sun, but will need to be kept well watered to bloom continuously in sunny locations. Place plants 18 to 24 inches apart in fertile, well-drained soil. To help retain soil moisture, spread a 3-inch layer of mulch around your plants.
Some folks say the spiderwort name comes from the way the flowers hang like spiders from a web. Some say it stems from hairs on the sepals and buds that glisten like a spider's web when covered with dew. And some attribute the name to the plant's gooey sap, which looks like a strand of silky spider web when stretched. That sap, by the way, is surely the reason why the plant is known as "cow slobber" in some parts of the country. There are many different species of spiderwort, with common names ranging from Virginia Spiderwort to Confederate Spiderwort. Talk to the people at your local garden center, arboretum, or native-plant society to find out which one is right for your area. There is an Asian plant that goes by the name of spiderwort, and it's considered an invasive plant. Be sure to get a native variety.