The best form of the tiny 'Bluets' from N. America, this has dainty, four-petalled flowers of sky blue with white and yellow centres over low, spreading mats for many weeks, starting in early spring. It's a lovely plant for a cool, slightly moist and lightly shaded area but it will do well anywhere that doesn't get too dry.
About 7cm (3") high, slowly trailing in habit. Houstonia may be trimmed back when required - it will quickly recover and flower again. Left alone, it will flower for weeks.