This robust diploid (2n = 10) is widespread across eastern and central North America, except on the southeastern Coastal Plain. It can prosper on damp to dry, fertile soils, especially in old fields, but it is greatly reduced by browsing animals. There is considerable variation in overall size, form, pubescence, flower color and season; also, several distinct selections are used in horticulture (including dwarf plant with deep color). However, natural segregates have not been recognized in most treatments. An unusual short, bushy, white-flowered variant with low seed production has been recently discovered growing wild in MADI (J. Perry, pers. comm.), and a relatively smooth, short, pinkish variant in HART (T. Barnes, pers. comm.), propagated by Roundstone Seed Inc. The latter is similar to cultivar "Alma Potschke" but seems to be spontaneous in a population with much variation in color; it flowers much earlier, mostly in late Jun-Aug (versus Aug-Oct). During 2024 in FAYE (on Willowood Road) flowering of some cultivated plants has been observed as early as June 9th. There may be rare hybrids with pilosum, which have been erroneously named X amethystinum (Nutt.) Nesom in Ky. (Short & Peter 1835; F, St, BA, M). That name applies to hybrids with ericoides (FNA 20).