It's a cruel trick of Mother Nature that that most glorious weather of the gardening season coincides with the decline of most blooming plants. Not so with the aster (Asteraceae). Like garden mums, asters flower in response to the shortening days of fall, giving gardeners a carpet of daisy-like flowers on a compact plant from August through October, depending on the variety. Although home and garden centers market asters as a seasonal impulse purchase among displays of pumpkins and hay bales, asters are long-lived perennials that you'll want to make a permanent part of your landscape. Though aster flowers have that wildflower look, they make are also beautiful in vases as flower arrangements. People aren't the only ones who find asters attractive; pollinators such as bees and butterflies also love aster flowers. If they're planted in the fall, asters can be one of only a few sources of late-season nectar, making them a crucial flower for the pollinators.
The best time to plant asters is in the springtime when it's still slightly chilly and the air becomes more humid. The most common types of asters in North America are New England asters and New York asters. The former usually bloom in bright purple or magenta while the latter fall into the bright pink and bluish-purple color schemes. The family Asteraceae contains the genus Symphyotrichum, which encompasses the 90 or so recognized aster species. Asters also go by the name Michaelmas daisy, a nod to the Feast of St. Michael, which falls on September 29, when asters are in peak bloom. While you can grow aster flowers from seeds in the springtime, you may find them easier to grow when you buy them as potted flowers that you transfer to soil and in loamy, well-draining soil.
The perennial aster is a wildflower, but horticulturists have produced new colors and tidier plants for the cultivated landscape:
'Celeste': Early blooming; dark blue flowers with bright yellow centers
'Hazy': Early raspberry-pink flowers with yellow centers
'Puff': A white aster hardier than many other white cultivars; very early blooms
'Professor Kippenburg': Clear blue flowers on a compact plant
'Winston Churchill': Early bloomer with dark pink flower