Glabrous, usually perennial; stems usually branched from the base with decumbent, divaricate, straggling branches 20-70 cm. Leaves 8-22 x 2-11 mm, broadly elliptic-oblong to linear-oblong, mostly alternate. Flowers trimorphic, solitary in the leaf-axils, suberect. Hypanthium 5-6 mm, shorter than the subtending leaf, cylindrical-obconical, tapered gradually to the base, spotted with red near the base. Sepals broadly deltate, scarious; epicalyx-segments c. 1 mm, triangular-subulate, equalling or somewhat exceeding the sepals. Petals 5-6 mm, purple, sometimes white or cream at the base. Stamens 12, some or all exserted. Capsule much shorter than the hypanthium.
Best grown in medium moisture, well-drained soils in full sun to part shade. Tolerates some drought. Remove spent flower spikes to encourage additional flowering. Cut back to basal foliage in fall, or earlier if plant appearance declines. Appreciates a site protected from strong winds. Stems may be cut back in spring if shorter plants are desired. Plants may freely self-seed in the garden if spent flowers are not promptly deadheaded, however some self-seeding is desirable in order to keep this short-lived perennial in the garden.