Spiderwort (Tradescantia virginiana) is a herbacious perennial that blooms from late spring to mid autumn, and tolerates all types of sun, but flourishes in mid shade. It grows to about two feet.
Native to North America but considered invasive, spiderwort is a grassy looking plant that self-seeds and creates clumps. And its flowers are beneficial to bees. But beware: the leaves can cause mild irritation.
There are about 70 species of tradescantia, which is named after John Tradescant the Elder (1570s - 1638) and John Tradescant the Younger (1608-1662), who introduced the plant to English gardens.