Smooth Blue Aster (Laeve)

The Smooth Blue Aster (Laeve) is generally described as a perennial forb/herb. This is native to the U.S. (United States) has its most active growth period in the spring and summer . The Smooth Blue Aster (Laeve) has green foliage and inconspicuous purple flowers, with a moderate amount of conspicuous brown fruits or seeds. The greatest bloom is usually observed in the mid summer, with fruit and seed production starting in the summer and continuing until fall. Leaves are not retained year to year. The Smooth Blue Aster (Laeve) has a short life span relative to most other plant species and a moderate growth rate. At maturity, the typical Smooth Blue Aster (Laeve) will reach up to 4 feet high, with a maximum height at 20 years of 0 inches.

The Smooth Blue Aster (Laeve) is usually not commercially available except under contract. It can be propagated by bare root, seed. It has a slow ability to spread through seed production and the seedlings have low vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -43°F. has medium tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Conservation: Smooth blue aster is used for mixed-grass and tallgrass prairie restoration as well as roadside revegetation.

Gardening: The showy flowers of smooth blue aster makes it a popular plant for use in wildflower, native plant, and butterfly gardens.

Wildlife: Smooth blue aster is palatable to white-tailed deer, which prefer to graze this species before other forbs. It has high nutritional value, decreasing with maturation. It also attracts butterflies, pollinators of the flowers, and can provide shelter for them.

General Characteristics

General: Aster Family (Asteraceae). Smooth blue aster is a perennial forb with a stout rhizome and underground stem (caudex). Six to seven aerial stems sprout from the caudex. Plants are generally 30 to 100 cm tall. Leaves are thick and stout, 1 to 2.4 cm wide and less than 5 times as long as wide, sometimes toothed along the margins and clasped to the stem by a lobed appendage (auricle). Leaves near the inflorescence are reduced to 2 mm bracts and have diamond-shaped tips. Each plant produces several inflorescences. Ray flowers are pale blue to purple, 7 to 15 mm long. Disc flowers are yellowish. Fruit are achenes. Flowering occurs from August to October. Lower leaves drop early in the autumn while upper leaves remain until frost top-kills the plant.

Required Growing Conditions

Smooth blue aster is native to the United States. It occurs from Maine to British Columbia, south to Georgia and Arkansas, and west to New Mexico. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.

Habitat: Smooth blue aster occurs in various habitats, ranging from moist woods to dry, open prairies. It is most notably associated with mixed prairie plant types, and is also a dominant understory species in quaking-aspen communities.

Adaptation USDA hardiness zones for smooth blue aster are 4 to 8. Smooth blue aster occurs on various soil types. It was found to sustain more populations on wet, poorly drained glacial till in eastern Illinois and western Indiana. In Michigan it occurs on xeric sites more readily than on mesic and transitional sites. It is not tolerant of deep shade, but does well in high light to intermittent shade conditions.

Cultivation and Care

Smooth blue aster seeds are ready for collection in September when achenes separate easily from the receptacle. Dry seeds prior to cleaning and store in sealed containers at 3 to 5oC. Damp stratification at 1 to 2oC for 2.5 to 4 months may increase seed germination of higher elevation sources. Seed storage longevity is up to 7 years.

Seeds can be started in the greenhouse from December to March. Cover seeds to one times their depth with soil and lightly press down. Seeds germinate in 10 to 15 days at 22oC, reaching the true leaf stage in 7 to 15 days. Seedlings should be thinned and fertilizer can be applied biweekly once the true leaf stage has been reached. Foliage must be thoroughly rinsed off after fertilizer application. When foliage is 8 to 10 inches tall, prune plants back to 3 to 4 inches.

For the first 12 weeks, 20-10-20 liquid NPK fertilizer at 100 ppm is applied. Plants are then fertilized once with 10-20-20 liquid NPK at 200 ppm. After 4 weeks, seedlings can be stored in outdoor temperatures under insulating foam (if necessary) for up to 5 months before outplanting. Outplanting can take place from September to November or April to May.

General Upkeep and Control

Deer grazing does not affect survival of established smooth blue aster plants as long as only stem tips are removed. Most plants respond to grazing with vigorous growth the next growing season.

Herbicides used to control quack grass can suppress establishment or growth. These herbicides contain glyphosate, dichlobenil, picloram, tebuthiuron, and hexazinone, alone or in combination with each other.

Smooth blue aster resprouts from the rhizome after being top-killed by fire. In general, late spring fires have more adverse effects on percent plant coverage, and perhaps on leaf and flower regeneration, than early spring fires.

Plant Basics
Growth Rate Moderate
General Type Forb/herb
Growth Period Spring, Summer
Growth Duration Perennial
Lifespan Short
Plant Nativity Native to U.S.
Commercial Availability Contracting Only
Physical Characteristics
Bloom Period Mid Summer
Displays Fall Colors Yes
Shape/Growth Form Rhizomatous
Drought Tolerance Medium
Shade Tolerance Intolerant
Height When Mature 4
Vegetative Spread Moderate
Flower Color Purple
Flower Conspicuousness Yes
Fruit/Seed Abundance Medium
Fruit/Seed Seasonality Summer Fall
Seed Spread Rate Slow
Gardening Characteristics
Propagations (Ways to Grow) Bare Root, Seed
Moisture Requirements Medium
Cold Stratification Required No
Minimum Temperature -43
Soil Depth for Roots 10
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Slow
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5.8–7.8 pH
Precipitation Range 20–20 inches/yr
Planting Density 2700–11000 indiv./acre
Soil Textures Coarse, Medium
Soil Depth for Roots 10
Minimum Frost-Free Days 100 day(s)
Salinity Tolerance None
CaCO3 Tolerance Medium
Sustainability & Use
Leaf Retention No
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA