Smooth Aster (Symphyotrichum laeve) typically occurs in prairies, rocky glades, dry open woods, roadside banks and thickets. Stems are usually unbranched with variable, mostly toothed, smooth, bluish green foliage. Small flowers with violet blue to purple (sometimes white) rays and yellow center disks appear in open, loose, panicle-like clusters in autumn. The root system is fibrous and rhizomatous. Older plants may develop small woody caudices. Occasionally, clonal offsets are produced from the rhizomes.
After blooming the florets are replaced by achenes with small tufts of tawny (less often white) hair; they are distributed by the wind. Individual achenes are 2-3 mm. long, narrowly oblongoid-oblanceoloid in shape, slightly flattened, and variably colored (usually some shade of gray or brown with whitish fine ribs). The root system is fibrous and rhizomatous; older plants may develop small woody caudices. Occasionally, clonal offsets are produced from the rhizomes.
Habitats include mesic black soil prairies, hill prairies, savannas, rocky open woodlands, sandy woodlands, woodland edges, thickets, limestone glades, and roadside embankments. Smooth Blue Aster is usually found in higher quality natural areas where the original ground flora is intact. It is sometimes cultivated in gardens because of its attractive foliage and flower heads.
This plant usually remains erect while in bloom and it is able to tolerate hot dry weather if it is not too prolonged. The foliage is occasional marred by powdery mildew and other foliar diseases to some extent; good air circulation reduces this vulnerability. Smooth Blue Aster is easy to cultivate in gardens if taller and more aggressive plants are kept away from it.