There are more than 600 species of true asters, ranging from 6-in.-high alpine kinds forming compact mounds to open-branching 6-ft.-tall plants. Flowers come in white or shades of blue, red, pink, lavender, or purple, mostly with yellow centers. Bloom time comes in late summer to early fall, except as noted.
Taller asters are invaluable for abundant color in large borders or among shrubs. Large sprays effective in arrangements. Compact dwarf or cushion types make tidy edgings, mounds of color in rock gardens, good container plants.
True asters are adapted to most soils, but growth is most luxuriant in fertile soil. They have few problems except for mildew on leaves in late fall. Strong-growing hybrids have invasive roots; they can regrow from small fragments left in soil and spread to become nuisances. Divide yearly in late fall or early spring. Replant vigorous young divisions from outside of clump; discard old center. Divide smaller, tufted, less vigorously growing kinds every 2 years.Aster ericoides
Native to eastern North America. Grows to 3 ft. tall and 1 ft. wide, with narrow leaves and strong horizontal branching. Flower heads are small and profusely borne, in white, pink, or blue.
Bears rose-pink flowers in fall.
Plant is 1 ft. tall and 2 ft. wide; has lilac blooms and resists mildew.
From the Pyrenees. Forms wide, 8–12-in.-tall mats composed of 1–1 1/2-in., soft gray-green...