Heath aster in bloom

Heath aster (Aster ericoides) is now in bloom. This dry-prairie plant has a stem/leaf structure like a Brillo pad, which is probably where the common name comes from. It has a dense cluster of bright white flowers, and in a brilliant sunny day such as today its flower heads fairly glow.

This is one of the late-blooming plants of autumn, although vegetative plants are visible early in the summer. I assume it is a short-day plant, and initiation of flower bud formation does not begin until the days start to get short.

According to my phenology, it is one of the last species to flower in the fall, some plants still showing fresh flowers as late as the end of October. There is nothing rare about this species in Wisconsin, although it is listed as endangered in the state of Tennessee. On the other hand, it is said to be invasive in Nebraska and the Great Plains.

Some people may be dismayed to learn that botanists no longer use the genus name Aster, although it is still used as a common name. What used to be Aster is now called Symphotrichum. I'm willing to use "some" of the new Latin names, but I plan to stick with Aster. As somebody once said, "the plants don't care what their names are."

When it is in a favorable habitat, heath aster can form large patches, spreading by means of underground rhizomes and stolons. I have seen patches of 6-8 feet in diameter, although it never misbehaves the way Canada goldenrod does.

At Pleasant Valley Conservancy, heath aster is most common on our very dry south-facing slope, although it also can be found in other places. The photo here was taken in the south unit of Toby's Prairie, which does have a slope to the south and gets fairly hot in full sun.