Stokes Aster Flowers

When giving some thought recently about fall-blooming, perennial flowers the ever-popular chrysanthemum or mums as they are usually called, was the first to come to mind. However, there is another flower that is a fall bloomer called Aster. There are many different kinds with varying heights and flower colors. They are easy to grow and they are a great source of nectar for bees, butterflies and other pollinators, providing some late-season nectar during the fall.

When choosing what kind of Aster to plant into your landscape or garden, the basic qualities to look for are height, bloom time, bloom color and sun/soil requirements. Most Asters are happiest in full sun (8+ hours), but some will tolerate partial shade (4 to 8 hours) but they may not bloom quite as prolifically or be as vigorous.

I want to add just a note about choosing the flower color. I would recommend not planting a white flower against a white house. That white flower will not add a pop of color or show up as well as, for example, a purple or pink one would.

Asters grow best in loamy, moist, but well-drained soil. Some varieties will grow well in clay soil. They do not like “wet feet”. Mix some compost into the soil before setting them into the planting hole. Asters can be planted almost anytime during the growing season, but I would not recommend doing so during the heat of summer. That time is stressful for any perennial to be planted and stressful to those trying to keep it alive. To give the roots time to grow and anchor the plant in the soil, plant Asters in the early fall. After the first frost, place 1 to 2 inches of mulch around the base of the plant to prevent any heaving or damage during the winter.  Vigorous plants may need to be divided every three to four years. Whenever you choose to plant or divide or transplant anything, I recommend adding a root stimulator to the water. I have had much success with that practice.

Asters come in various heights. The taller varieties will need to be staked and all will do well by having the growth pinched back at least two times during early summer, with the last pinching around the 4th of July holiday. Pinching or shearing back the plant will promote bushier growth and more buds. After the first killing frost, you can cut the stems back to an inch or two above the soil line. I like to leave the stems of my Asters and Mums standing to collect leaves which provides winter protection for the crown.

Keep an eye on your Aster plant. If you notice it is not flowering as well as it had in the past and the vigor has gone out of it, it may be time to dig it up and divide it. It may need this every three to four years.

The main disease affecting asters is powdery mildew. This usually appears from late June to July as a whitish growth on the leaves. To help prevent this, start spraying the plant with a horticultural oil/fungicide starting in mid to late June. Sprays need to be applied before the disease becomes established and throughout the season. Generally, powdery mildew does not cause any harm to the plant, it just lessens the overall beauty of the plant.  Always read, understand and follow label directions when using chemicals.

As always, Happy Gardening!

More information about gardening and related subjects is available online at  The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.