T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Tradescantia virginiana (Virginia spiderwort)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
(unranked): Commelinids
Order: Commelinales
Family: Commelinaceae
Subfamily: Commelinoideae
Tribe: Tradescantieae
Subtribe: Tradescantiinae
Genus: Tradescantia
Species: Tradescantia virginiana
Synonym: Tradescantia virginica.
Common names: Virginia spiderwort, Lady's Tears, Spiderwort, Spider lily, Common spiderwort, Dayflower, Flower-of-a-day, Job’s tears, snake-grass, spider-lily, Trinity, Trinity-lily, Widow’s-tears

Tradescantia virginiana is a large, perennial, herbaceous, clump forming plant that is native to North America. It was introduce to New Zealand as a garden plant and is now fully naturalised.
It has narrow, arching, bright-green, iris-like leaves on tubular stems that can be 0.5-1m tall. 
The leaves themselves are up to 30 cm long and 25 mm wide and are folded lengthwise forming a groove. If the stems is cut, a viscous stem secretion is released which becomes threadlike and silky upon hardening (like a spider's web), hence the common name.
It has three-petaled, hermaphrodite flowers which are up to 5 cm across. They are blue-violet in colour but occasionally are white. They have bright, yellow stamens. The flowers are borne in summer on a terminal cluster containing numerous flower buds. The flowers open only in the morning and later in the day they wilt and turn to a jelly-like fluid.

It can self-sow and become a nuisance in the garden and occasionally will escape into the wild. Tradescantia virginiana will hybridise in just about any combination.