Knapweed takes root in local areas

Bruce Shaull, Beth VanCampen, Peter Schay and Candia Bernstein of Camp Sherman pluck knapweed.

It's August and those pretty purple flowers of the noxious Spotted Knapweed (Centaurea maculosa) or its close relative Diffuse Knapweed (Centaurea diffusa) are in bloom.

A group from Camp Sherman, led by Beth Van Campen, was collecting, bagging and destroying knapweed plants recently along Highway 20, near Sisters in front of the Threewind shopping center.

"Beth is the driving force for our group," says Bruce Shaull of Camp Sherman.

These efforts temporarily lessen the knapweed but don't eliminate all the plants or seeds. It's an ongoing battle, and a community effort. Les Schwab Tires has donated the large tire bags for collecting knapweed over the past two years by the Camp Sherman group.

Why the concern? The flowers are pretty, but knapweed, a non-native species, pushes out local native plants. Knapweed tends to spread and dominate an area, reducing diversity and overall beauty.

Out in Camp Sherman there are about two-dozen sites identified as major knapweed habitats in the Deschutes National Forest. Van Campen visits the Little Montana site off Road 828 and keeps an eye on about a two-acre stand of knapweed.

The nearby stream bed, when flowing, carries seeds downstream. Van Campen and her crew picked here last year but it is a difficult area to walk, pick and carry out the knapweed plants in large bags ­ particularly for mature adults.

Spraying by herbicide offers other problems. The chemicals can be carried downstream and get into the wild and scenic Metolius River causing potential problems for the trout populations.

In these forest areas, the knapweed beats out native vegetation that provide feed for deer and elk. Since the animals don't eat knapweed, this reduces their food supply and ultimately can lead to starvation. Also, knapweed stands tend to increase soil erosion.

The City of Sisters has an ordinance stating "No person in charge of property may permit or cause to exist vegetation that is an invader species such as Knapweed."

The city occasionally uses Roundup or 2-4D to control knapweed populations on city lands, according to Gary Frazee, Sisters Public Works Director.

However, walking through the industrial park lots and then towards city hall gives evidence of how tenacious the weed can be.

The Forest Service is preparing a report about knapweed in our local forest areas and how to remedy the problem.