Where do noxious weeds come from and how are they spread?
Noxious weeds and non-native invaders began to appear and spread with European settlement and continue to arrive today. Most of Oregon’s least desirable weeds are of Mediterranean, European, and Asian origin. The introduction of non-native invasive plants has increased dramatically in the past decade due to the increased ease and speed of world travel and the expansion of global commerce. Local spread of noxious weeds can be natural by wind, water, and animals; but human activities such as, recreation, vehicle travel, and the movement of contaminated equipment, products, and livestock often greatly increase the distance and rate of dispersal.
