Noxious & Invasive Species

Program Contact: Debbie Williams, County Extension Director
(509) 524-2685 • dmoberg@wsu.edu

Yellow Starthistle
Yellow Starthistle

What is a weed? Any plant growing where it is not wanted may be considered a weed. All weeds are obnoxious but ‘noxious weed’ is a legal term for any invasive, non-native plant that threatens agricultural crops, local ecosystems or fish and wildlife habitat.

About half of all invasive, noxious weeds are escapees from gardens. Read plant descriptions before purchasing new plants for your garden. Beware of any that are described as “aggressive”, “free seeding”, “easy to grow” or even “ground cover” as they may very easily grow out of control.

It is often easier to prevent weeds in the first place than to try to control them later.  Whenever soil is disturbed, dormant weed seed is brought to the surface where it may germinate. Managing weeds usually requires perseverance, as many weed seeds remain viable in the soil for years.  Keeping desirable plants healthy is also a great way to crowd out unwanted weeds.  If you examine your landscape or garden on a regular basis, you can often remove weeds before they become out of control.

Use the least harmful method to control your weeds.  Favor hand pulling or cultivating over spot spraying and spot treating individual weeds rather than spraying an entire area.  Always identify the weed (2017 WA State Noxious Weeds List) you need to manage so that you can use the most effective removal method at the highest vulnerable time of the weed’s life cycle.

Do you need help identifying your weeds and the most effective way to manage them?  Samples may be brought to the Extension office for identification and for suggestions of cultural and/or herbicide control.

zebra mussels
zebra mussels

Eastern Washington Guide to Non-Invasive Plants for Your Garden

What is an invasive species? Any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem; and whose introduction does or is likely to cause economic or environmental harm or harm to human health.