Perennial herb 23 - 45 cm tall Leaves: opposite, stalkless, longer than wide, 2.5 - 5.5 cm long, 1 - 2.5 cm wide, egg- to lance-shaped with either blunt or pointed tips, but rarely sharp-pointed tips. The lower leaves are almost hairless, while the upper leaves are soft-hairy, and fringed with slender bristles, but never glandular-hairy. Inflorescence: terminal, loose and open branched, covered with fine, gland-tipped hairs, and having nine to thirty flowers. The two lowest branches of the inflorescence are usually at least 1 cm long, and normally subtended by a pair of short, narrow, opposite bracts. Flowers: short-stalked, 2 - 3 cm wide, lavender to violet, though occasionally white, often with a darker center (may appear as a purple ring), radially symmetric, with a slender tube, and abruptly flared lobes. The flowers have a delicate fragrance. Sepals: five, 0.7 - 1.1 cm long overall, but fused for up to half their length, then separating into very narrow, linear lobes with an abrupt, up to 0.5 mm long, sharp tooth at the tip. Petals: five, but fused into a 1.2 - 1.8 cm long, hairless tube, then separating into 1.3 cm long, 0.8 cm wide, inversely egg-shaped lobes, which are normally rounded at the tip, and lack notches. Stamens: five, with filaments attached at different heights along the inside of the petal tube, but never extending beyond the petal tube. Pistil: with a single, three-chambered, superior ovary; and three, short (1.5 - 3 mm long, usually shorter than stigmas or ovary), fused styles, which separate about midway into three, linear stigmas. Fruit: a three-valved, three-chambered, egg-shaped capsule with one (rarely two), relatively large (2 - 6 mm long), ellipsoid seed per chamber. Stems: softly long-hairy, low, decumbent, trailing on the ground and rooting at the nodes, with erect, leafy, flowering shoots.

Similar species: Phlox divaricata ssp. laphamii is more common in the Chicago Region than the typical subspecies, P. divaricata ssp. divaricata, which normally has 1 - 3 mm deep notches at the petal tips. Phlox divaricata ssp. laphamii is fairly similar to P. pilosa and its subspecies, but those taxa have abruptly narrowed, sharp, stiff leaf tips; usually hairy petal tubes; and sepals with very long, pointed tips. Other species of Phlox in the Chicago Region are either low, decumbent plants, or the style is very long, and much exceeds the length of the stigmas or ovary.

Flowering: April to June

Habitat and ecology: Very common in Chicago Region woodlands, preferring calcareous soils.

Occurence in the Chicago region: native

Notes: The flowers of this plant attract butterflies, moths, and even bees.

Author: The Field Museum