A real late bloomer

On a recent early November trip to Sunrise Mountain in Stokes State Forest in New Jersey, I checked the weather on the summit. It was a partly cloudy morning with a ten to 20 mph northwest wind and cold, about 26 degrees—just about right for migrating hawks, falcons and eagles I hoped to see that morning.

A check the surrounding area for any perched passerines or other birds nearby revealed none, only low brush and the trees that dare to grow in this rocky, windswept summit. I scanned the scrub oak, pitch pine, and some small white pine, many wind damaged. Most of the trees and other plants had either lost their leaves or had brown, desiccated leaves that would rattle with the wind gusts. I looked down at the ground and spotted only a couple of plants and tufts of grass that were still green. With some surprise, I noticed that there were some plants that not only had green, but purple flowers as well.

A close look at this plant revealed it to be spotted knapweed (Centaurea biebersteinii). This member of the aster family is a short-lived perennial, growing up to four feet and displaying an attractive purple flower, and the bracts of the flower heads are black tipped. Each plant can produce up to 400 seeds per flowerhead. It is also considered an invasive species, originally making its way to America from central Europe via contaminated alfalfa seeds and dirt used as ship’s ballast.

In Western states, the spotted knapweed, and other related species, are considered a significant threat to pastures and grazing land. Several states have aggressive campaigns to control and prevent the spread of this weed.

In this area, this plant is less of a threat but still considered an invasive plant. It may have been introduced to the pavilion area when the pavilion was first built in the 1930s by the CCC, perhaps by fill soil during foundation construction. Spotted knapweed is not prolific at this site, but it has survived a long time here. Flowering as late as November and growing in this location speaks a lot for its robustness.