PlantFiles: Smooth Blue Aster
Symphyotrichum laeve

Medium-sized (for an aster) light blue to pale violet/lavender ray flowers with yellow disk flower centers. The better-known New England aster is more purple than the smooth aster. Bright green, smooth, long, narrow foliage. One of the showier prairie native asters, IMHO. In our rich NE Iowa soil we get specimens in the 4-5' range. Blooms from August to the first hard frost.

Hardy, drought tolerant, and does well in dry to even slightly wet mesic soil, as long as it is well-drained. It reseeds fairly vigorously, and so can be a bit more aggressive than the somewhat smaller showy blue sky-blue aster (Symphotrichum oolenlentangiensis, A. azureus, A. oolentangiensis). Germinates readily in warm soil without cold stratification. In fact, we've had better germination results sowing indoors in the spring than when we've fall sown outdoors or done any cold treatment.

Attracts butterflies and other pollinators. I like it mixed with the more delicate, diminutive flowered sky-blue aster, and the vivid golden flower stalks of the showy goldenrod (Solidago speciosa), both of which are similar in height and bloom time.

This smooth aster is a Missouri native that 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 (.75 to 1.25" across) with violet blue to purple (sometimes white) rays and yellow center disks appear in open, loose, panicle-like clusters in autumn. Attractive to butterflies.