Although the flowers are pretty and mostly edible, the Ohio spiderwort can be an aggresive self-seeder and considered a weed. The leaves are similar to grass blades, and the flowers are small, making them somewhat difficult to detect in small numbers.
Tradescantia ohiensis (Ohio spiderwort, Bluejacket)
Hardiness Zones: 4-9
Height: 61-91 centimeters (24-36 inches) tall
Diameter: 46-76 centimeter (18-30 inch) spread
Growth Rate: moderate to fast
Root System: extensive, easily spreads by rhizomes
Subspecies: var. foliosa, several hybrid specis
Tolerates: drought, dry soils, not susceptible to most insect/disease problems
Problems (major): none
Problems (minor): Snails may harm young foliage. Capable of self-seeding, can spread aggressively.
Poisonous: The sap may irritate the skin, causing dermatitis.
Soil requirements: Moist, acidic, and sandy or loam or clay soils are preferred, dry soils tolerated.
Air requirements: not sufficiently researched, insignificant
Watering requirement: dry to medium
Sun requirement: full sun (prefers, blooms better in) or part-shade
Leaf shape: Dark-green or blue-green basal (originate from one point) leaves look like blades of grass.
Leaf size: up to 42 centimeters (18 inches) tall and 4 centimeters (2 inches) wide, stems grow anywhere from 15-115 centimeters tall
Flower structure: inflorescences consist of 3 flowers (typically purple or blue) up to 3 centimeters (1.5 inches) in diameter in clusters (up to 20, although typically 3 or 4 are open on any one day)known as “cymes”
Flowering frequency: May-July, each few flowers in a cluster remain open for only one day. Produces dark grey/gray seeds in capsules (which contain up to 6 seeds) that require roughly 120 days of stratification for successful germination.
Bulb/tuber: neither, consists of an extensive root system
Apparently edible, T. ohiensis is sometimes used in salads.
The crushed leaves are sometimes used as an insect or arachnid bite remedy.
An Ohio spiderwort in Osaka-fu Japan (uploaded 17 June 2007, originally from http://en.wikipedia.org/wiki/File:Tradescantia_ohiensis2.jpg)
I do not own the rights of this image; all credit goes to its original creator(s).