Tatarian aster is an impressive, stately perennial with a flowering height of 3 to 6 feet. It can look you in the eye yet require no staking. More important, this aster flowers longer than any other garden aster, beginning in late September and early October and continuing into November. The 1-inch-wide, light lavender flowers are a magnet for local and migrating monarch butterflies. This plant tolerates many soil types, can form large colonies in a few years, and is easily divided.