Thursday, August 26, 2010

Teasel control in a sedge meadow

The Skokie Lagoons bird monitoring team - Linda G., Mary Lou M., and Dolph W. - has struck again. These citizen scientists have made careful observations at key areas of the Skokie Lagoons preserve for years. This spring, though, they were dismayed to find that one of their favorite locations on their monitoring route had been invaded by teasel, a nonnative, invasive plant that is capable of crowding out all other vegetation. The sedge meadow area (north of the Willow Road parking lot) that had been formerly productive for shrubland birds was becoming disappointing birdwise, and the teasel invasion was a likely culprit.

The bird monitoring team took the initiative to contact the humble volunteer site stewards (including yours truly) and Forest Preserve District of Cook County (FPDCC) staff to make sure that the sedge meadow was included in the 2010 Skokie Lagoons management plan. With the stewards' enthusiastic approval, the bird monitors went on the offensive in July, braving the summer heat and humidity to cut the seed heads off the mature teasel plants and remove the stalks. In some areas, the prickly teasel stalks were taller than the volunteers!

Teasel towers over bird monitor Linda during a removal workday. Photo courtesy of Mary Lou.

On July 20, the FPDCC brought in the big guns: their contractor, Tallgrass Restoration, applied herbicide to teasel plants over the whole sedge meadow area. Within two weeks, much of the teasel was dying. Volunteers, including a local Boy Scout troop, continued to work to remove the dead stalks and to pull any new growth. Now that much of the teasel is gone, the meadow is already showing visible signs of recovery - some amazing wildflowers are emerging.

Teasel has a two-year life cycle, so the area will require continued work and monitoring. The plan going forward is to target the first-year growth of teasel (the low-to-the-ground rosette form) with herbicide this fall to preempt next spring's growth. By herbiciding in the fall, collateral damage to next spring's native plants is avoided. Linda and Dolph have obtained their herbicide operator and applicator licenses from the Illinois Department of Agriculture to help keep the program going (under the stewards' supervision, of course). The war on teasel is not yet won, but it's definitely moving ahead.