Asters are barely noticeable in spring and summer, but with the shorter days and cooler temperatures of autumn comes a wonderful surprise in the form of dazzling daisy like flowers in a wide range of colors from snowy white to hot raspberry pink to soothing shades of blue and purple. While many of our native asters can grow to overwhelming sizes, some of the hybrids are short in stature. I like ‘Purple Dome’ because, with a mature height of only 18 to 24 inches, I don’t have to worry about it appearing leggy at the end of summer just when it begins to draw the most attention. ‘Alert’ is even more compact, growing 12 to 15 inches tall. It is the perfect size for the front of a flower border and for containers. This is not to say that I don’t grow a few of the behemoths such as ‘Alma Potschke’, which reaches heights of 3 to 4 feet. A trick I use to control the varieties of queenly proportions is to keep them pruned back until early July. After the last pruning the plant will flush with new growth and set flower buds that will open in mid to late fall.
Asters are actually very easy to grow. They require full sun and thrive in average garden soils. When they’re happy, they can be vigorous growers and may require dividing every two to three years.