Spiderwort is characterized by a grass-like form with long, strappy leaves similar to lilies that grow up to three feet in height each season. Quarter-sized, three-petaled flowers open in the morning and close by early afternoon, each bloom lasting just one day. Luckily, each plant produces many buds throughout spring and into early summer. The flowers attract pollinators including butterflies and are of special interest to native bees. The plants may hybridize in any combination. Spiderwort should be planted in the spring. As spiderwort can cause contact dermatitis, it is considered toxic to humans, and toxic to pets. Deadheading may be necessary to encourage repeated blooming of your spiderwort. As a native wildflower, spiderwort does not have any serious pest or disease problems.
Light
Spiderwort is not overly picky about available sunlight. While the plant tends to prefer partial shade, it does well in almost any environment, as long as it gets at least a few hours of light per day and enough water if exposed to all-day sunlight. That being said, you will notice a difference in the amount and frequency of blooms depending on how much sunlight your spiderwort gets, so choose a sunnier spot if you’re hoping for an especially showy plant.
Soil
Spiderwort is easily grown in almost any soil condition, as long as it is moist but well-draining—it thrives best in humusy soil that boasts a slightly acidic pH of 6.8 to 7.2. Because the plant tends to clump and sprawl as it grows, it’s best planted in the spring, four to six inches deep in the soil, with about a foot or more between each plant to give them ample room to grow.
Water
While spiderwort is a drought-tolerant plant, it does best in moist soil and should be watered every few days, especially during the hotter summer months. If you live in an area with frequent summer storms, chances are your natural environment will provide enough rain to keep your spiderwort plants happy.
Temperature and Humidity
Spiderwort is not picky when it comes to its temperature and humidity conditions. It is adapted to a range of hardiness zones and can tolerate a variety of temperatures, allowing it to thrive from early spring to late summer. Because spiderwort plants like moisture, they will do fine in humid climates but do not require any added humidity if it’s not naturally present in your environment.
Fertilizer
For spiderwort plants grown outdoors, there is very little need for fertilizer. A single application in early spring at the beginning of its growing period is usually sufficient. For the amount to use, follow the product label instructions. If you’d like to give your plant additional nutrients throughout the summer, you can add compost to your soil.
Types of Spiderwort
Many tradescantia varieties available in nurseries are hybrids that have been developed by breeders with a focus on leaf and flower color. They include:
Tradescantia ‘Amethyst Kiss’, a trademarked variety with purple-blue blooms that can grow in full sun, partial shade, and full shadeTradescantia ‘Concord Grape’ with pinkish-purple flowers and blue-tinted leaves suited to full sun or partial shadeTradescantia ‘Red Grape’ with bright rose-colored flowers and a compact, mounded growth habitTradescantia ‘Sweet Kate’ stands out by its bright yellow leaves that contrast well with its saturated blue flowers.Tradescantia ‘Purple Profusion’ has multiple buds on the flower stems and the young foliage is purple-tinged.
Pruning
The major drawback of spiderwort is its tendency to look ragged after its bloom period is over. The solution to this issue lies in mid-season shearing. This practice serves two purposes: First, it prevents spiderwort from self-sowing and becoming weedy. Second, shearing the plant back by one-third (leaving around eight to 12-inch stems) or de-leafing to new growth will reinvigorate the plant, increase your chance of late-season blooms, and make it look more presentable for the rest of the season.
Propagating Spiderwort
The easiest way to propagate spiderwort is to divide large clumps in the fall or early spring. Dividing them not only gives you a new plant for your yard, or to give away, but it also tidies up the plant.
How to Grow Spiderwort From Seed
Spiderwort will readily self-seed so if you want to increase the number of plants in your garden, you can forego the midsummer shearing and let the plants go to seed. Starting plants from seeds yourself is trickier as some varieties require a period of cold moist stratification, while other varieties have an extended germination period of 30 days or more. Also keep in mind that unless you purchase seeds for a specific cultivar from a seed company, the seeds that you collect from your plants may not produce plants that are true to the parent and your seed-starting efforts might yield unpredictable and disappointing results. That being said, the propagation of spiderwort by dividing existing plants is the better way to go.
Potting and Repotting
While spiderwort species such as Tradescantia pallida and T. zebrina can be grown in containers as houseplants, T. ohiensis, T. virginiana, and T. subaspera (the species covered in this article) are best suited to be planted in a garden setting due to their fast-growing nature and sprawling habit.
Overwintering
Spiderwort is hardy to USDA zone 4band does not need any winter protection.
How to Get Spiderwort to Bloom
Given that spiderwort is such as prolific bloomer in its first year and soon after planting, it is unlikely that it fails to bloom at all. The more sun the plant gets, the more it will bloom. If it stops blooming, cut it back by one-third as described in the Pruning section.
