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April 27, 2007

King County wants to rip out noxious weed problem by the roots

King County Noxious Weed Program offering free workshops for landowners

When 5-year-old Henry Weiker developed painful blisters on his skin a couple of weeks ago, his mother didn't know what to do.

Following a neighbor's suggestion, Wendy Weiker called the King County Noxious Weed Program for advice, where she learned that a noxious weed called giant hogweed was growing in the yard of her Mercer Island home where her son was playing.

Henry came into contact with the weed's watery sap, which causes the skin to be hyper-sensitive to sunlight and leads to painful burns and blisters. Fortunately, the youngster has made a full recovery from his painful injuries.

Giant hogweed can grow as tall as 15 feet when in flower and has leaves 3 to 5 feet across. When it is allowed to go to seed, hogweed forms dense, imposing infestations in ravines, parks, backyards and alleys.

Giant hogweed is one of 43 state-listed noxious weeds that the King County Noxious Weed Program is actively trying to control. Noxious weeds are non-native plants introduced to Washington that cause damage to the natural or economic resources of the state.

Where noxious weeds are still limited in distribution, landowners are responsible for controlling them. When one of these noxious weeds is found, the county weed program informs the responsible agency or landowner and works with them on a plan to control it before it spreads.

Giant hogweed is an example of a Class A noxious weed – the highest priority for eradication – due to the nasty burns it causes and because of the environmental damage that can result if it is left unchecked.

"The highest priority weeds are those that King County still has an opportunity to eradicate or at least stop their spread,"said Noxious Weed Program Manager Steve Burke. "The key to success is finding infestations early, and for landowners and public agencies to work together to control them."

Examples of high priority noxious weeds that are still in an early phase of invasion in King County include:

  • Garden loosestrife, a yellow-flowered wetland plant has the potential to be worse than the more widely known purple loosestrife;
  • Garlic mustard, a quick-spreading forest invader that is already a huge problem in the eastern United States;
  • Policeman's helmet, a pretty but highly invasive annual that rapidly takes over streamside areas; and
  • Phragmites, a tall invasive grass that crowds out native wetland species.

Burke said some of the weeds that pose the highest potential threat to King County agriculture include tansy ragwort, milk thistle, meadow knapweed, goatsrue and sulfur cinquefoil. Information on all of these weeds and many others is available on the program Web site: www.dnr.metrokc.gov/weeds.

In addition to working individually with landowners, the King County Noxious Weed Control Program offers free workshops on invasive and noxious weeds.  There are classes scheduled throughout the county from early May through early July. All classes are free and open to the public. Details are available at www.dnr.metrokc.gov/weeds/classes.htm.  

  • Ornamentals Gone Bad, May 19, 1-2 p.m., Furney's Nursery, 21215 Pacific Hwy S, Des Moines
  • Renton Noxious Weed Workshop, May 24, 6:30-8 p.m., Renton Senior Center, 211 Burnett Avenue N., Renton
  • Snoqualmie/North Bend Weed Workshop, June 5, 7-8:30 p.m., Meadowbrook Farm Interpretive Center, on Boalch Avenue Northwest, between Snoqualmie and North Bend
  • North King County Pasture Weeds Workshop, June 13, 7-8 p.m., Woodinville Library, 17105 Avondale Road NE, Woodinville
  • Seattle Backyard Invasives, June 21, 7-8:30 p.m., Northgate Community Center, 10510 5th Ave NE, Seattle
  • East King County Pasture Weeds Workshop, June 26, 7-8 p.m., Maple Valley Library, 21844 SE 248th St., Maple Valley
  • Burien Backyard Invasives, June 27, 6:30-8 p.m., Burien Community Center, 425 SW 144th St., Burien

Community associations are encouraged to contact the county weed program if they would like to schedule a presentation on noxious weeds in their area. For more information, contact the weed program's education specialist Sasha Shaw at 206-263-6468 or by email at sasha.shaw@kingcounty.gov.