Are Aster Flowers a Bush?

The aster is a colorful addition to late summer and fall gardens.

With the exception of the annual China aster, asters are perennial flowering plants that bloom in shades of white, blue, red, pink or purple with yellow centers. Most varieties flower from late summer through early fall. They can range in size from 2 inches to 7 feet tall. While asters are not a bush plant, some varieties grow in large clumps and one bears the name bushy aster (Aster dumosus).

Mythology

Aster flowers were once placed on altars as they were considered sacred to the gods, and in medieval Europe, the leaves were burned to repel snakes. Aster is the Latin word for star, and the original plant name in English was starwort. They were renamed Michaelmas Daisy in honor of St. Michaelmas Day, which coincides with the aster's bloom time in September.

Varieties

The Asteraceae family is a large and diverse group that includes sunflowers and dandelions, as well as asters. Today's hybrids derive primarily from two native lines: the New England aster (Aster novaeangliae) and the New York aster (A. novibelgii). One such hybrid is the Alpine aster, a rock garden plant with violet flowers that blooms in May in June. The bushy aster grows to 3 feet tall and displays numerous 1/2- to 3/4-inch lavender flowers from August to October. Bushy aster is a perennial wildflower that inhabits fields, meadows, and thickets and propagates by seed and rhizome.

Uses

Asters are excellent in butterfly gardens. The New England aster, for example, attracts red admiral, painted lady, monarch, pearl crescent, white and sulphur butterflies. The sky-blue aster and smooth aster also attract a number of butterflies. The more compact varieties can be grown in containers and many of the tall cultivars are good as cut flowers.

Growing Asters

Asters are propagated by cuttings, seed or division. Gardeners usually purchase hybrid plants in garden centers. The plants like fertile, moist, well-drained soil and full sun. Most varieties grow in large clumps, which should be divided every few years. The taller asters should be staked, but pinching the flowers early in the season can make them sturdier and more compact. Pinching will, however, delay the bloom time. If hybrid asters self-sow, remove the seedlings as they will not reproduce true to color.

Insect Pests and Diseases

Asters may be bothered by several insect pests, including aphids, cottony cushion scale, caterpillars, leafhoppers, leafminers, scale, spider mites, thrips, lace bugs, weevils and whiteflies. If picking them off or spraying them with a garden hose doesn't do the job, treat the plants with an organic or chemical pesticide. Asters are also susceptible to aster yellows, fasciation, fusarium wilt, gray mold, leaf spots, powdery mildew, root and stem rot, rusts and viruses. Regularly dividing the plants and discarding the center of the clump will help keep the plants healthy and able to resist most diseases.

References

• University of California: Aster -- Aster Spp.
• University of Vermont Extension; Asters and Goldenrod: The Mythology; Leonard Perry
• Fairfax County Public Schools: Bushy Aster
• "The Garden Primer"; Barbara Damrosch; 1988

Resources

• Colorado state University Extension: Fall Asters
• Ohio State University Extension; Butterfly Gardens; Kathi L.Borgmann