I love the fall asters. They bring so much color to our gardens and countrysides. They also are some of the last nectaring and pollen plants available for the insects — the butterflies, moths, bees and flies — that we so intently watch as they go about their busy lives. Later on they are a good seed source for birds and small mammals.
Sky Blue Aster (Symphyotrichum oolentangiense)
According to Illinois Wildflowers, the daisy-like flowerheads of the Sky Blue Aster which is sometimes called Azure Aster are typically “lavender or light blue (rarely white), linear-oblong in shaped, slightly notched at their tips, and widely spreading. The tiny corollas of the disk florets are tubular in shape with 5 ascending to spreading lobes along their upper rims; these corollas are initially yellow, but they later become purplish red and finally brown.”
Frost Aster (Symphyotrichum pilosum)
Again, according to Illinois Wildflowers, the daisy-like flowerheads of the Frost Aster are typically “white (rarely light pink or light blue-violet), linear-oblong, and widely spreading when the flowerheads are fully open. The corollas of disk florets are yellow and short-tubular in shape with 4-5 recurved lobes. Later, the corollas of disk florets become reddish purple to reddish brown.” The uniqueness of this aster is the small leafy bracts that grow along the branches.
Note: Like most asters, the leaves of these two gradually taper toward their bases where they clasp themselves around the stem.
Pinching Back Asters
Like many of the asters, when a native plant is in bloom, it often leans to one side because of the weight of the flowerheads. Don’t hesitate to pinch back asters or almost any native plant beginning in June if you wish to control their stature. Native plants are very resilient to storm damage, having evolved with whatever Mother Nature throws at them. So, I believe it’s safe to assume that native plants will typically withstand some simple pruning.
P.S. I say this from experience because of my witness to hail damage to native plants in July at the WILD Center in 2010. After cutting back the hail damaged stems, the native plants proceeded to continue growing and produce blooms just as if nothing had happened to slow down their progress.