Spiderwort (Tradescantia)

Hairy Stem Spiderwort, Indian Paint, Purple-heart, Spiderwort, Tradescantia

Spiderworts include perennial wildflowers that are commonly cultivated as ornamental plants in North America and Europe. Some species are used as houseplants while other, more temperate species are used as ground covers in gardens. Because of their easy propagation, some species have become invasive in the Southern U.S., New Zealand, and Australia.

I. Appearance and Characteristics 

Tradescantia is a genus of 85 species of herbaceous perennial wildflowers in the family Commelinaceae, native to the Americas from southern Canada to northern Argentina, including the West Indies. Members of the genus are known by many common names, including inchplant, wandering jew, spiderwort, dayflower and trad.

The genus’s many species are of interest to cytogenetics because of evolutionary changes in the structure and number of their chromosomes. They have also been used as bioindicators for the detection of environmental mutagens. Some species have become pests to cultivated crops and are considered invasive.

Tradescantia are herbaceous perennials and include both climbing and trailing species, reaching 30–60 centimeters (0.98–1.97 ft) in height. The stems are usually succulent or semi-succulent, and the leaves are sometimes semi-succulent. The leaves are long, thin and blade-like to lanceolate, from 3–45 cm long (1.2–17.7 in). The flowers can be white, pink, purple or blue, with three petals and six yellow anthers (or rarely, four petals and eight anthers). The sap is mucilaginous and clear.

A number of species have flowers that last for only a day, opening in the morning and closing by the evening.

The first species described, the Virginia spiderwort, T. virginiana, is native to the eastern United States from Maine to Alabama, and Canada in southern Ontario. Virginia spiderwort was introduced to Europe in 1629, where it is cultivated as a garden flower.

The natural range of the genus as a whole spans nearly the entire length and width of mainland North America, from Canada through Mexico and Central America, and thrives in a great diversity of temperate and tropical habitats. It is frequently found in thinly wooded deciduous forests, plains, prairies, and healthy fields, often alongside other native wildflowers.

II. How to Grow and Care

Sunlight

Bright indirect light is best for growing tradescantias. They may survive in lower light conditions, but may experience elongated, weak growth and leaf drop. Low light levels also cause fading of both leaf color and variegation. Similarly, direct light exposure may also lead to color loss. Plants grown in bright indirect light will have more vibrant foliage. Place your tradescantias near east, south, or west-facing windows.

Temperature and Humidity

Any of the species of spiderwort plants will thrive at temperatures between 65 and 75 degrees Fahrenheit, and they’ll also do fine in warmer temperatures. However, the plants should not be kept in sustained temperatures below 50 degrees Fahrenheit, as it might discolor or damage their leaves.

When it comes to humidity levels, spiderwort plants love above-average moisture. Start by keeping them in a typically humid area of the home, like a bathroom or kitchen. You can also mist the plant lightly every few days or invest in a small humidifier. If you notice the plant’s leaves browning, it could be a sign that humidity levels in your home are too low.

Watering

Tradescantia likes moist soil that dries out between waterings. Water thoroughly until water starts to pour out of the drainage holes. Overwatering is a major cause of tradescantia decline and death. Tradescantias will rot if their crowns are constantly wet. If preferred, bottom watering can be performed to prevent overwatering.

To do this, fill a large container or sink with water. Insert the pot slowly, bottom-side down and allow water to enter through the drainage holes until the soil is evenly moist. Tradescantias are native to humid, tropical environments and appreciate high humidity. Dry air may lead to tip browning of leaves, especially in winter. Pebble trays with water or regular misting will provide humidity for tradescantia.

Soil

Spiderwort plants can grow well in ordinary potting soil, as long as it’s not over-watered. Overall, they prefer soil that drains well; their roots can easily develop rot if they remain too wet. To aid in drainage, mix a small amount of sand into a commercial potting soil blend that also boasts an ample amount of organic material.

Fertilizing

Tradescantias should be regularly fertilized to encourage lush growth. Feed your tradescantias monthly throughout the growing season of spring through fall. Select a well-balanced fertilizer formulated for indoor use. A liquid fertilizer works well when used with irrigation. Dilute the fertilizer to half-strength, as too much fertilizer may affect leaf color and cause tip browning. Avoid fertilizing during winter.

Planting Instructions

Choose a sturdy, heavy pot that is more wide than it is deep for your tradescantias. These plants are shallow rooted, with most of their growth occurring above ground. Because of this, tradescantias may get top-heavy and are prone to tipping over if particularly vigorous. Pots should be 1-2” larger than the root ball with adequate drainage. Use a well-drained potting mix with added perlite. Tradescantias should be repotted once roots start poking out of the pot’s drainage holes. Repot in mid-spring once the growing season has started. This helps to reduce transplant shock and promote active growth. Wear gloves while potting and handling tradescantia, as some people experience irritation from its sap. 

Pruning

Spiderwort is an aggressively growing plant that can get overly leggy if left untamed. To keep your plant in check (and encourage it to grow wider and fuller), cut the stems back periodically, trimming back to a joint. To avoid legginess, regularly prune or pinch back the stems by at least 25 percent.

Propagation

Many tradescantias propagate themselves via layering, when stems come into contact with the soil. In this process, roots will develop on the stems in between the nodes, forming new plants. Another popular method of propagation is by taking stem cuttings. Using clean scissors or shears, take a cutting that is approximately 3” long. Remove the lower leaves and place in a glass of water. Change out the water often. Once roots grow to roughly an inch long, remove the cutting from the glass and place in well-drained soil. Stem cuttings can also be propagated directly in moist soil. While not required, rooting hormone may speed up the process. Tradescantias should be pinched back often to obtain a fuller habit, which leads to several opportunities to propagate the pinched stems.

Growing Tradescantia Outdoors

Most species of tradescantia can be grown outdoors as perennials in USDA zones 9-11, or as annuals in zones with colder winters. There are some perennial species, such as Tradescantia virginiana, that are native to cooler regions of North America (zones 4-9). Tradescantias grow best in light, dappled shade. They tolerate a wide range of temperatures and can be moved outside after the danger of frost has passed, and then moved back inside before the next frost in autumn. Tradescantia does well when planted in containers with other shade-loving annuals, where it can cascade along the sides of the pot. Acclimate all indoor tradescantia plants to outside light by keeping them in a fully shaded spot, out of direct sunlight, for a few hours a day, eventually increasing the amount of time outdoors until fully acclimated.

Pests and Diseases

Root rot is a common problem in tradescantia; check for brown, squishy roots and stems. Prune off any mushy tissue and repot into dry soil immediately. Sometimes, the leaves of purple or variegated tradescantia may turn green if exposed to low light levels. Cut off green leaves to prevent them from taking over, and increase the amount of light the plant receives. While tradescantia is not particularly susceptible to pests and diseases, it may pick up aphids, whiteflies, scale, or fungus gnats from neighboring houseplants. Treat with horticultural oil per label instructions. Diatomaceous earth or biocontrols may help as well, especially with fungus gnats. If your tradescantia is not blooming, lower the temperature to 60°F through winter into spring, being sure to expose the plant to ample light. 

III. Uses and Benefits 

This forgiving easy-to-grow plant is suitable for beginning gardeners and has a wide range of uses, whether augmenting interior spaces or when planted in the landscape. Add spiderwort plants to shade gardens, woodland borders, containers, or hanging baskets.

Spiderwort (Tradescantia) Details

Common name Hairy Stem Spiderwort, Indian Paint, Purple-heart, Spiderwort, Tradescantia
Botanical name Tradescantia
Plant type Houseplant
Hardiness zone 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 10a, 10b, 11a, 11b, 12a, 12b
Growth rate Medium
Sunlight Dappled Sunlight (Shade through upper canopy all day)
Soil condition Clay
Flower color Blue
Leaf color Green