Virginia spiderwort, Tradescantia virginiana, is a perennial native to the deciduous forests of the eastern United States. It is easy to grow. Tradescantia is not overly particular about soil quality, nor does it require watering once established. Spiderwort gets its name because the fluid that seeps from cut stems dries to look like a spider web.
Many gardeners grow hybrid varieties of spiderwort that have more showy flowers than the native species. In addition, most people grow it in massed groupings. I would do neither.
I would follow the lead of the State Botanical Garden of Georgia.
I disliked Tradescantia for years. I never wrote about it because I had nothing positive to say. It wasn’t the plant’s fault. Spiderwort in its native landscape is lovely. The reason for my bias against spiderwort had more to do with seeing it poorly used in the garden than anything.
You will see ‘improved’ hybrid varieties of spiderwort grown in massed groupings, often in sunny exposures. The sun washes out the colors of the plants. The more gaudy hybrids trade size for charm. By mid-summer, spiderwort turns into a tangled mass of foliage that is a visual blight on the landscape. Gardeners could shear it back after flowering and thus revitalize it, but you see this rarely.
I never really saw spiderwort used properly in the landscape until I came upon it at the State Botanical Garden of Georgia. My opinion about Tradescantia changed completely.
There is a shade garden at the state botanical garden. It’s a wonderful place to view trilliums and mayapples and new fern fronds every spring. There, among the trees and the ferns are naturalized groupings of Virginia spiderwort. It is a quiet masterclass in garden design.
You will find the spiderwort in the upper part of the shade garden, mostly on slopes. Pockets of plants, none crowding the other, are interwoven throughout the botanical garden’s landscape. Tradescantia is not a dominant species here or in nature. A plant here, a plant or three there, that’s how it goes at the botanical garden with the spiderwort.
Waves of poppies dominate the early spring landscape in the sunnier parts of the botanical garden. The poppies are breathtaking. In the shade garden, especially the deeper parts of the garden, a different ecosystem is in place. Much of the shade garden is freer, with plants occupying a more naturalized environment. Most plants are found in small clusters intermingling with other species. This looks like a place where plants are introduced and allowed to fend for themselves. The result is a natural pattern that suits the human eye.
Learning how to site plants according to how they occur in their native habitat is a worthwhile way to garden.
Gardening with spiderwort – naturalize
The flowers are approximately an inch wide. Because of the relatively small size of the flowers, I suspect the temptation with gardeners and designers is to mass spiderwort in order to enhance the visual impact. Planting masses of small-flowered plants is normally a sound plan, but it won’t work with a plant such as Tradescantia.
By mid-season, the already wayward leaf stalks have flopped into an unruly mess. Further, spiderwort is a native plant of the eastern North American forests. Rarely are woodland perennials found massed in colonies. Ferns are an exception.
Plant spiderwort singly or in pockets in shady areas of the garden. Strive to make it seem like it naturally arrived at its location. Grow it among ferns and variegated Solomon’s seal. Don’t grow too much of it. Don’t crowd the plants.
Let it peek through the dappled sunny spots that inevitably occur in most shade gardens. Planted correctly spiderwort can teach us a lot about restraint in garden design.
Growing tradescantia, a few points
Like daylilies, each spiderwort bloom lasts for only one day, but subsequent buds open quickly to ensure a steady supply of flowers for pollinators.
Spiderwort is easy to grow. It prefers shade or partial shade. Partial shade translates to morning sun and shade in the afternoon. You don’t need to fertilize it much, especially if you plant it in woodland areas that have naturally rich soil. I never fertilize anything by the way. Every year in late winter I spread compost across the garden and move on. At the state botanical garden, I’d wager the woodland plants subsist on decaying leaf matter alone.
Once established, no supplemental watering is required. Tradescantia virginiana is winter hardy in zones 4 through 9.
After flowering, spiderwort can look ratty. You can cut it way back, which will stimulate new growth and flowers. If you do cut it back this will prevent seeds, which can be a good or bad thing depending on your perspective. If you naturalize Tradescantia, the foliage can be left to age naturally as other plants grow up around it.
You may see spiderwort offered as Tradescantia x Andersonia
Spiderworts native to the eastern United States interbreed between species. The hybrids that occur cannot be grouped into an existing species such as Tradescantia virginiana, Tradescantia ohiensis, etc. These hybrids, including many you will see for sale, are grouped into the scientific name Tradescantia x Andersonia.
A vast majority of the plants you see offered will have very similar, if not identical growth characteristics. The primary difference visually will be the color and size of flowers.