A spiky little menace popped up last year in Clatsop County.

Unbeknownst to home gardeners happily shoveling pickup loads of sawdust at the site, a patch of gorse had sprouted right next to a pile of the dust. The dense evergreen shrub, pregnant with highly burnable oil and capable of crowding out native vegetation, was in position to dispense seeds far and wide until some folks recognized the invader and removed it.

Dave Ambrose, who works with the Clatsop Soil and Water Conservation District in Astoria, says it is instances such as the above example that has prompted a group of Clatsop County agencies to come together to work out a plan for dealing with noxious weeds. The Clatsop Weed Management Advisory Committee received funding from the National Fish and Wildlife Foundation, the Oregon Weed Board and local sources to identify noxious weeds and to educate the public on how to handle the invaders.

For the home gardener, that message is to know noxious weeds and not to spread them, says Ambrose.

"I've seen instances where people cut things down, take the weeds and dump them and unknowingly allow them to grow elsewhere," Ambrose says. He says city gardeners need to be on the lookout for plants such as Japanese knotweed, an invader that has been labeled a hazardous waste material in England unless it is bagged when removed.

The local coordinating committee will focus on a handful of noxious weeds this year, including gorse, Japanese knotweed, Scotch broom, tansy ragwort, purple loosestrife and spartina grass. Justin Williams, an Oregon State University extension agent at the Clatsop County office, says CWMAC's public education campaign will include public weed identification events, such as last Sunday's demonstrations at the Astoria Sunday Market. He also envisions "weed walks" where residents can tour areas infested with noxious weeds.

As part of the effort, this column will feature a description and a photo of a noxious weed each month starting in July.

To gain noxious status, a weed must be designated by the Oregon State Weed Board as injurious to public health, agriculture, recreation, wildlife and any public or private property. There are 100 plant species officially designated as noxious weeds in Oregon. Some have become so thoroughly established and are spreading so rapidly on public or private land that they have been declared to be a menace to public welfare. The Oregon Department of Agriculture has established a quarantine to cut down the number of noxious weeds in the state. It is against the law to sell, offer to sell, purchase, or transport plants on Oregon's noxious weed list.

Williams says it's hard for home gardeners to determine whether or not some plants are weeds, and if they are weeds, whether the plant is invasive.

"The reality is that people see a pretty flower, such as the purple loosestrife, and think that it is a desirable ornamental," Williams says. He has received several calls lately about Scotch broom, many from people wondering why they should cut down the vibrant yellow blooms.

"If people don't deal with weeds such as Scotch broom, it will seed and spread," he says.

Williams encourages people with weed questions to call him at (503) 325-8573 or Master Gardeners at the same telephone number during the Master Gardener Hotline hours, noon to 3 p.m. Mondays and 10 a.m. to 1 p.m. Wednesdays. To report an invasive weed, call Dave Ambrose at (503) 325-4571. Information about invasive weeds also is available by calling the Oregon Invasive Species hotline, 1-866-invader.

Cathy Peterson belongs to the Clatsop County Master Gardener Association. "In the Garden" runs weekly in Coast Weekend. Please send comments and news to "In the garden," The Daily Astorian, P.O. Box 210 Exchange St., Astoria, OR 97103 or to peterson@pacifier.com