Noxious Weeds overview

Noxious weeds / invasive plants are one of the largest disruptors of ecosystem function. They can colonize a variety of habitats, reproduce rapidly with a variety of mechanisms, and aggressively out-compete native species.  A plant is designated noxious in Idaho when it is considered to be injurious to public health, agriculture, recreation, wildlife, or property.

Weeds are typically spread by dispersal of seeds or plant parts in a variety of ways. The wind, water, animals, machinery, and people carry seed and plant parts from one location to another. Many weeds produce abundant seeds with barbs, hooks or other attaching devices that facilitate easy adherence to people, animals or equipment. Because society has become increasingly mobile, weed seeds can and do travel great distances quickly. Weeds usually become established and advance along highways, roads, trails and river corridors. Some noxious weeds, such as purple loosestrife, have been spread through ill-advised horticultural and home garden plantings. Others have been inadvertently introduced through planting of contaminated crop seeds, the feeding of weed seed contaminated forage to livestock, or on vehicles, boats or other machinery.

For questions on noxious and invasive plants in your county, please contact:

Basic Plant Identification - Throughout the University of Idaho's Weed Identification Series, we use specific terms to quickly describe a weed’s life cycle, growth form, leaf arrangement and margination, root structure, and flower structure, all of which help viewers determine the key traits that set the weed apart from other plants. In the interest of time, we don’t define those specific terms in the individual weed identification videos. So the purpose of this video is to give you definitions and examples of those key words.

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+ Image Credits:

Banner Credit: (Orange Hawkweed) Michael Shephard, USDA Forest Service, Bugwood.org. Photo Credit: (left) Dale Morlan, Benewah County / (Right) Vic Ramey, University of Florida/IFAS Center for Aquatic and Invasive Plants.