Year-Round Gardening —Asters

Asters

Are the Last to Bloom

By Joyce Arleen Corson, Guest Columnist and Master Gardener

Blue wood aster is a herbaceous perennial that may grow 3 feet tall. It has narrow, alternate leaves with a toothed margin. Pale blue to violet flowers bloom in large, loose panicles. Aster blooms resemble a star, the symbol of love, wisdom, faith and color.

Aster azureus, sky blue wood aster, is a bright and showy addition to any sunny perennial garden. I have adopted the star as a favorite. The Latin name is symphotrichum cordifolium.

The multitude of brilliant blue blooms from late August into October combine well with the showy goldenrod for a fabulous fall appearance in contrasting colors. The standard aster color is purple or blue, but cultivars have been developed that come in a wider range of colors.

What makes them quite unique is the asters are the last of the flowering shrubs to bloom before frost. These fragrances of the wood aster and goldenrod are the signal of migration for many species of birds, bees, butterflies and other wildlife.

The pearl crescent butterfly uses the aster as their retreat. Bees remove honey from the hives before foraging begins of these final flowers. During this time frame, the pollen collection is used as food for the winter hive to make bee bread. The aster’s carefree green lance-shaped leaves have a lively look all season. The stems are there through summer without anyone paying much attention. They can be pruned on the Fourth of July to half their size. Do this when early blossoms twist and turn brown and the lean, dark violet-streaked stems give way to airy lavender-colored sprays of glassine blossoms, whose open petals are caught in a vivid yellow center.

Aster plant pruning is a must if you want to keep these perennial flowers healthy and blooming abundantly. Pruning is also useful if you have asters that grow too vigorously and are taking over your beds. Pruning asters is optional but there are some good reasons to do it. One is simply to maintain a shape and size that you like. Pruning them back can prevent the need to stake them and give the plants more pleasing shapes also.

One reason asters are so popular with gardeners is that they are easy to grow. They prefer full sun to partial shade and need well- drained soil. Blue aster flowers and other cultivars do well in zones 4-8. Our area’s zone is 5b, so they are bountiful here.

These are perennials that will come back year after year, so divide them every couple of years to keep the plants healthy. Also seedlings are easily recognized and can be moved to a new location or given as gifts to friends.

If you have rich soil, these flowers will grow abundantly and add more color to your garden. n