Aster, from the Latin for "star," is a hardy wild flower in the sunflower family. Their colours range from pinks and purples to red and white, and their size is just as variable, with plants that grow anywhere from 8-inch-tall dwarf asters up to standard 8-foot bushes. They are perennial and return to bloom each spring.
Plant asters in the early spring, spacing them one to three feet apart to allow for ample growth. Sow them from seed or plant from divisions or seedlings. Start seeds indoors or in a greenhouse in late winter and move outdoors in the spring when danger of frost is past.
Divide asters in the spring, as well. Division and moving of plants early in the spring as foliage appears gives the plants the maximum amount of warm weather to adjust to their new environment and strengthen their root systems before winter. Moving late in the year does not give the plant enough time to get established before harsher weather sets in, and plants have a lessened chance of survival. Do so by separating out the strongest shoots with about three shoots to a clump, and cut with a sharp shovel. Dividing keeps plants vigorous by eliminating overcrowding.
While the main complaint of standard asters is their tendency to lose the leaves near the ground, dwarf asters are much shorter and do not suffer this tendency. Plant dwarf varieties in front of standard asters to extend the beauty of their bloom. Asters bloom from the middle of August and into October, and pair well with other late bloomers such as mums. Dwarf varieties lend a splash of colour to annual border plantings, as well, since annuals are often done with their bloom as autumn approaches.
Asters are somewhat drought hardy, but do prefer an inch of water per week with a good dry-out between waterings. They need an average to rich soil that drains well, and do well in sun to partial shade. If moving late in the season, provide shade to keep from stressing the plant. Stake tall asters to keep them upright as they become top heavy.