The genus Tradescantia comprises some 75 herbaceous species. Tradescantia species are mainly from tropical and subtropical regions in the Americas and the Caribbean, where they are found in woodland and scrub habitats, and disturbed ground. They are evergreen perennials with trailing, creeping or tuft-forming habits, and fibrous or tuberous roots. Their fleshy, mucilage-filled leaves are often particularly obvious, being purple or variegated. Their delicate, short-lived, saucer-shaped flowers have three petals, ranging in colour from violet-blue and purple to pink or white, and three sepals. The fruit is a capsule or a berry.
The Swedish botanist Carolus Linnaeus named the genus in honour of a pair of English gardeners and plant collectors; the John Tradescants, father (1570-1638) and son (1608-1662). Tradescant the Younger introduced Tradescantia virginiana to England in 1629 from the American Colonies; blue- and white-petalled forms were grown in the Oxford Botanic Garden at least as early as 1648. During the 1600s, Tradescantia species spread through Europe and the rest of the world through trade. Today, many different Tradescantia species are naturalised in Europe, Asia, Africa and Australia.
Many Tradescantia species are economically important in the nursery trade and are widely available as ornamental and houseplants. In the temperate climate of the United Kingdom, there are hardy varieties of Tradescantia that die back over winter, especially Tradescantia virginiana, and those that are tender and need glasshouse protection, such as the popular houseplant Tradescantia zebrina.
Tradescantia species that are native to disturbed habitats in their native ranges are easy to cultivate, reproducing readily from tiny stem sections and root fragments. Such ease of propagation means that here these species have been introduced, as ornamental and houseplants in subtropical and tropical regions, they have often escaped the confines of cultivation, establishing themselves in natural habitats. Moreover, readily-propagate species that produce light, wind-dispersed seed are capable of long-distance movement meaning they may colonise areas remote from human influence.
Tradescantia species can form carpets of dense ground cover, preventing the germination and establishment of native plant seedlings; a feature that makes them attractive in horticulture. However, the large biomass of colonising Tradescantia species may alter litter decomposition and nutrient cycling, which in turn affects ecological succession. Tradescantia species that are now regarded as invasive weeds, include Tradescantia zebrina (inch plant), Tradescantia spathacea (boat lily), Tradescantia pallida (purple queen) and Tradescantia fluminensis (small-leaved spiderwort). In some regions, the sale of these species is banned.
Brickell C 2016. RHS A-Z encyclopedia of garden plants. DK.
CABI 2019. Tradescantia fluminensis (wandering jew). CABI Invasive Species Compendium.