Virginia spiderwort (Tradescantia virginiana), Virginia Native Plant Society 2008 Wildflower of the Year, is a long-blooming herbaceous perennial for native plant gardens

Overview

Virginia spiderwort (Tradescantia virginiana) is the Virginia Native Plant Society 2008 Wildflower of the Year. Virginia spiderworts were originally native from western Connecticut north to Wisconsin and south to Georgia, Tennessee, and eastern Missouri. However, they now grow naturally in twenty-five of the eastern U. S. states, California in the western USA, and into the Canadian province of Ontario.

Plant Description

Virginia spiderwort plants form 3-foot-clumps of thin bright green branched stalks with long, narrow green to blue-green leaves. The stalks carry clusters of blue (less commonly purple, red, or white) three-petaled flowers up to 2 in. or more in diameter. Generally, plants in VA bloom from April to July.

Use and Control In Landscape Gardens

Virginia spiderworts with their cousins, hybrids, and cultivars, are long-blooming perennials. They exhibit their finest features in:

• native plant gardens,
• woodland or shade gardens,
• wild gardens, or
• naturalized areas.

Their low growth and daily flowers also add interesting dashes of color to edges of perennial borders in filtered or dappled shade. However, when planted in full-sun perennial borders, summer foliage declines causing unattractive messes.

On the other hand, these plants spread so rapidly in favorable growing conditions that cultural control is necessary. Here are two simple techniques that keep spiderworts confined:

• Remove stems that bend over or sprawl in contact with soil. This keeps stems from rooting at nodes and producing new plants that extend the plant's growing area.
• Divide mature plants every two years to confine them and maintain the original planting scheme.

Growing Conditions

Virginia spiderworts thrive in sunny meadows, open woods or wood edges where soil:

• is moist but well-drained,
• includes organic matter (humus),
• is close to a neutral pH (6.8 – 7.2),
• does not contain much lime (CaCO3), and
• there is some leaf mulch.

These plants grow best in full morning sun, but need filtered or dappled afternoon shade to protect moisture-filled tissues. They bloom in the morning, close by mid-day and last only one day. Consistently deep shade causes floppy anemic plants that flower poorly or not at all.

Species, hybrids, and cultivars

Names and places of cultivated spiderworts in the plant heirarchy are confusing. Here are some examples that might make it easier to understand catalogs and labels.

The Royal Horticultural Society Plant Finder (RHS) lists four cultivars of T. virginiana:

• 'Alba';
• 'Brevicaulis';
• 'Caerulea plena'; and
• 'Rubra'.

Tradescantia species hybridize in just about any combination. Most spiderwort cultivars result from cross-fertilization among T. virginiana, T. ohioensis, and T. subaspera. These are sometimes listed as T. x andersoniana hybrids,the Anderson or Andersoniana group, or by their cultivar name.

Cultivar selection is primarily by flower color, and secondarily by clump-forming ability and plant height. Here are some of the best Anderson group cultivars for garden landscapes:

Blue and Purple Flowers

• 'Isis' : University of GA Professor Allan M. Armitage regards this cultivar as one of the best blue-flower-producing cultivars; it is also a recipient of the RHS Award of Garden Merit;
• 'J.C. Weguelin': also a recipient of the RHS Award of Garden Merit;
• 'Concord Grape' : 12-inch-high clump-forming plant.

Carmine and Red Flowers

• 'Red Cloud' : Armitage regards this plant as one of the best overall cultivars available. The red flowers are striking.

White Flowers

• 'Osprey' : large white flowers and blue feathery-appearing stamens create another recipient of the RHS Award of Garden Merit;
• 'Snowcap' : Armitage regards this plant as having the purest white large flowers.

Unusual Flower and Foliage Combinations

• ‘Sweet Kate': triangular, violet-blue blossoms with sulfur-yellow stamens and brilliant gold foliage; and
• ‘Blue and Gold': gentian-blue flowers with gleaming gold foliage.

Some nurseries list 'Sweet Kate' and 'Blue and Gold' as synonymous, one-in-the-same; however, the RHS, currently lists them as separate cultivars.

©Text by Georgene A. Bramlage. 2008. Photographs as noted. Reproduction without permission prohibited.