Growing like weeds

Ran on Monday, August 13, 2007

Growing like weeds
Workers cut 164 tons of unwanted plants out of Half Moon Lake

By Keighla Schmidt
Leader-telegram Staff

In 24 days of weed-cutting this year, city workers harvested 164 tons of weeds, up from last year's 98 tons, said Phil Johnson, the city's parks superintendent.

But it still wasn't enough to stay ahead of the plants that make the lake green during summer.

City officials like to begin cutting weeds when the DNR identifies there are 13 nodes on plants so regrowth is less likely, Johnson said.

"We're trying to cut in a timely manner to reduce the size of the weed beds around the lake," he said.

City and DNR officials said weather was the main factor in the failure of cutting this year.

"The lakes got warm very early," said Buzz Sorge, a DNR lake management planner. "The ice came off very early."

The weeds, an invasive exotic plant called curly-leafed pondweed, grew faster than usual.

Besides clogging the lake in early summer, the curly-leafed pondweed causes algae blooms to grow when it dies and releases nutrients. The nutrients make the algae grow.

The curly-leaf pondweed dies in late June and then releases reproducing turions that grow about a foot before the cold weather forms ice. Then, while the native plants remain dormant, curly-leaf grows a few more feet while it's still cold. In the spring it starts growing before native plants and takes over the shallow lake.

Officials said they could consider 16-hour cutting days instead of eight hours or buying another weed harvester for about $110,000, but the cost likely is prohibitive.

"We just can't afford to do that," Johnson said.