A battle is on to protect some of King County’s best riverside habitat from knotweed, a tough, invasive plant.

A workshop planned for 7 p.m. Wednesday, July 9, at Meadowbrook Farm Interpretive Center will help Valley homeowners fight back against the weed.

“Knotweed spreads when floods move root fragments downstream, so control involves starting at the top of the waterway, then moving downstream and systematically removing all knotweed in the floodplain,” said Steven Burke, manager of the King County Noxious Weed Program.

The noxious weed program regularly receives calls from homeowners who have been unable to get rid of knotweed on their property in spite of years of hard work, said Sasha Shaw, noxious weed program education specialist.

“Homeowners are often frustrated by the massive roots of the knotweed and its ability to regenerate year after year despite their best efforts,” she said.

The noxious weed program’s knotweed projects address the highest priority infestations, including those that are directly in upper watershed shorelines and floodplains. Knotweed growing in people’s backyards, along roadsides, in parks and elsewhere in the county, is beyond the scope of these projects.

The upcoming knotweed workshops will teach participants why knotweed is so invasive and hard to control, and offer practical information on how to effectively get rid of knotweed.

Class participants will get to see a knotweed stem injector in action, and learn how this tool can be used in an overall strategy to eliminate knotweed. Workshop participants will also learn what is being done to fight knotweed in each watershed, and what work remains.

For information, visit www.kingcounty.gov/weeds or call (206) 296-0290.

Meadowbrook Farm Interpretive Center is located at 1711 Boalch Ave., North Bend.