Asters are perennials. Here's some info about asters The Aster produce large clusters of delicate daisy-like flowers in white, purple, lavender, pink or red. They are hardy in USDA zones 4 through 9, depending on the variety. Asters should be planted in moist well-drained soil in full sun, but they will tolerate light shading. The plants form broad bushy clumps, so plant them at least 18 inches apart. Mature clumps will need to be divided every 3 - 4 years in the early spring, or late fall after the flowering has finished. Pinch back the tops by 6-8 inches at least once during the summer, to create a bushier plant and to prolong the fall bloom. This pinching MUST be done prior to mid July, or it will have an opposite effect, and blooming will be reduced. Asters may be propagated by dividing or grown from seed sown indoors at about 70 degrees F. or may be sown directly into the garden after all frost danger has passed. Germination takes anywhere from 15 to 30 days, depending on the temperature. Annual varieties of Asters require the same basic care, but should not be planted in the same spot the following year, to prevent plant diseases such as Aster wilt. Sow seeds directly into the garden in early spring, when all frost danger has passed. Barely cover the seeds with 1/8 inch of fine soil. Thin the young plants to 12 to 15 inches apart when they are three inches tall. Successive plantings will ensure a longer blooming season. Promptly remove any spent flowers to help ensure blooming throughout the summer. I guess they also come in annual varieties - I didn't know that.