Smooth Blue Aster

Symphyotrichum laeve

Species distinguishing characteristics: 

  • Leaves often clasp stem
  • A waxy, whitish bloom covers smooth foliage
  • 15–30 pale blue to purple, petal-like ray flowers surround a button of yellow disk flowers 
  • Narrow, green bracts with whitish bases and sharply pointed tips

Family Characteristics: 

  • Multiple layers of bracts beneath the flowers
  • Flower heads composed of many smaller (often tiny) flowers, each of which produces an individual seed
  • Flowers may contain disk florets, such as those in the yellow center of a daisy, and/or petal-like ray florets
  • Undivided leaves
  • Includes the food plants lettuce, artichoke, and endive

Growth habitat: 

Erect perennial, 30–100 cm tall, from short, stout rhizomes.

Leaves and stems: 

Foliage is covered with a waxy, bluish-white bloom and is hairless.  Thick, alternate, linear to egg-shaped leaves, 8–18 cm, are occasionally toothed along the edges.  Lower leaves are often withered.  Stem leaves are smaller, stalkless, and usually clasp the stem.  The uppermost leaves near the flower heads are tiny, 2 mm, and have diamond-shaped tips.


Several pale blue to purple flower heads, 1.5–2 cm across, in branched, leafy clusters that bloom from the bottom up.  Each flower head has 15–30 petal-like ray flowers, 7–15 mm long, that surround a central button of yellow disk flowers.  Beneath each flower head is several rows of overlapping, narrow, green bracts that taper sharply to a point and whitish at the base.  The outer bracts of the uppermost flower heads are shorter than the inner bracts.  Flower clusters and the area just below the clusters are not glandular.



Short, stout, reddish rhizomes and fibrous roots.


Hairless, hard-coated seeds (achenes) with a reddish tuft of hairs at the tip.

Habitat preferences: 

Open forests, stream banks, roadsides, and other disturbed areas at low- to mid-elevations.

Interesting facts: 

White-tailed deer (Odocoileus virginianus) and wild turkeys (Meleagris gallopavo) favor young plants as food, but their nutritional value diminishes as they mature.  The flowers attract many butterflies (Papilionoidea spp.) and other insects for pollination.  The Greek word aster means “star” and describes the star-like flower heads.  Smooth blue aster can be used for restoration in grassland ecosystems and along roadsides.

Biological Classification: