Non-native plants, also called introduced or alien plants, are plant species that were introduced into an area by humans either accidentally or deliberately.
A native plant is one that naturally occurred in an area prior to European-American settlement.
A weed is a plant growing in an undesirable location – it can be non-native or native, and what some people consider a weed in one location is a valuable plant in another location. Red alder, for example, is an important native pioneer and streamside tree in Western Washington but is considered a nuisance weed by many people because it spreads aggressively and grows quickly in fields, driveways, and yards.
Noxious weed is a legal term that is used to describe an invasive, non-native plant species that threatens our natural resources or economy – the plant’s presence poses a risk to agricultural production, water quality, or ecology. Washington State as well as each County maintains a noxious weed list.
You can learn more about Noxious Weeds and Noxious weed identification at the Washington State Noxious Weed Control Board Website or Snohomish County Noxious Weed Control Board