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Aromatic Aster

Symphyotrichum oblongifolium

Common names:
Aromatic American aster, eastern aromatic aster, fall aster, wild blue aster, shale aster

Content Detail

Despite the name, the flowers and foliage of aromatic aster only releases a balsam-like scent when crushed. The blue or bluish-violet, daisylike flower heads with their yellow centers bloom from late summer to mid-fall. Aromatic aster can be planted in rock gardens, native gardens, pollinator gardens, cottage gardens, naturalized prairies, naturalized meadows, beds, or borders with full to partial sunlight and well-drained soils. This species is native to the Chicago region according to Swink and Wilhelm’s Plants of the Chicago Region and current research.

  • Family (English) Aster
  • Family (botanic) Asteraceae
  • Tree or plant type Perennial
  • Native locale Chicago area, Illinois, North America
  • Size range Medium plant (12-24 inches), Large plant (more than 24 inches)
  • Light exposure Full sun (6 hrs direct light daily), Partial sun / shade (4-6 hrs light daily)
  • Hardiness zones Zone 3, Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8
  • Soil preference Dry soil, Moist, Sandy soil, well-drained soil
  • Tolerances Alkaline soil, clay soil, Dry sites, Occasional drought, Road salt
  • Season of interest late summer, early fall, mid fall
  • Flower color and fragrance Blue
  • Shape or form Broad, Irregular
  • Growth rate Moderate
  • Wildlife Butterflies, Game birds, Insect pollinators

Size and method of spreading:

Aromatic aster is between 1 to 3 feet tall and wide at maturity. These plants spread by sending out long stem structures along the surface of the soil (stolons) that produce offsets. They also spread by self-seeding. 

Native geographic location and habitat: (include C-value if appropriate)

The native range of aromatic aster includes the Eastern and Central United States. C Value: 9.

Attracts birds or pollinators: 

Aromatic aster attracts bees, gamebirds, butterflies, and skippers. 

Leaf description:

Aromatic aster has bluish-green leaves that are covered in short, stiff hairs, giving the plant an ashy appearance. The leaves around the base of the plant and on the lower stems have short stalks (petioles) or are stalkless (sessile). The lower leaves are long and narrow with blunt tips and tapered bases (oblanceolate) and are likely to fall off before the flowers bloom. The upper leaves have more tapered tips, have wider bases (lanceolate), are densely crowded, and reduce in size as they ascend the stems. The leaves can grow up to 2 inches long and one-half-inch wide, but most of the leaves are half this size or less. 

Leaf description:

Aromatic aster has bluish-green leaves that are covered in short, stiff hairs, giving the plant an ashy appearance. The leaves around the base of the plant and on the lower stems have short stalks (petioles) or are stalkless (sessile). The lower leaves are long and narrow with blunt tips and tapered bases (oblanceolate) and are likely to fall off before the flowers bloom. The upper leaves have more tapered tips, have wider bases (lanceolate), are densely crowded, and reduce in size as they ascend the stems. The leaves can grow up to 2 inches long and one-half-inch wide, but most of the leaves are half this size or less. 

Flower description:

Aromatic aster flower heads are daisylike composites of 20 to 35 blue to bluish-purple, narrow, petallike ray flowers and a center of 30 to 50 yellow disk flowers that mature to a reddish color. The numerous ray flowers help to distinguish aromatic aster from similar aster species. These composite flower heads are between 1 to 1 ½ inches in diameter and occur in branched, open clusters (panicles) at the terminal ends of the branchlets. Surrounding the bases of the flower heads are four to six layers of narrowly oblong, reflexed, leaflike structures (bracts). 

Plant Care:

Aromatic aster prefers moist to dry soils in full or partial sunlight. Providing adequate air circulation helps prevent powdery mildew issues.

List of pests, diseases, and tolerances:

Pests of aromatic aster include deer, rabbits, and caterpillars of butterflies and moths. Aromatic aster is tolerant of salt, alkaline soils, and sandy or clay soils as long as they are well-drained. It is susceptible to powdery mildew.

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