Weeds/Invasive Plants
Introduction
What is a ‘weed’? One would think it would be easy to figure out,
but with the variety of terms used to describe them these days, it can be confusing. Terms like ‘invasive’, ‘noxious’, ‘exotic’, and
‘non-native’ often only make it more difficult for the average homeowner to understand what they should and shouldn’t be concerned
about. Here is one way of wrapping your head around the ‘weed’ situation.
An exotic or non-native plant is a plant species that did
not naturally evolve in the region it inhabits; a non-natural component of the ecosystem. Not all exotic/non-native plants become
problematic. For an interesting article on ornamental weeds,
click here...
An invasive plant is a plant species that is non-native
to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to
human health. The category of invasive plants includes noxious plants (see below), as well as exotic plants that have the potential
to become unnaturally dominant on a site without intervention.
A noxious plant is an invasive plant that has been officially listed
as a problem species by a Federal, State, or County government as requiring various management actions and restrictions.
Some states
may include several native plant species on their list of noxious weeds. Colorado does not consider any native species to be a noxious
weed. The Colorado Noxious Weed Act defines noxious weeds as plant species that are not indigenous (native) to the state of Colorado
and meet at least one of several criteria regarding their negative impacts upon crops, native plant communities, livestock, and the
management of natural or agricultural systems. This definition applies to species listed by both state and local governing bodies.
The Federal noxious weed list contains species that are problematic in different states throughout the United States. The State of
Colorado noxious weed list contains species that are problematic within Colorado. The local County noxious weed lists contain species
that are problematic within that particular County, and varies by County. Information about weed species of most concern in your area
should ideally be found at the County level. Of highest priority are those species listed on the noxious weed lists, but there are
also plenty of other troublesome weeds that have not yet ‘made the list’ that you should keep your eye out for.
Federal Noxious Weed
List
http://plants.usda.gov/java/noxious?rptType=Federal
State of Colorado Noxious Weed List
http://www.colorado.gov/cs/Satellite?c=Page&cid=1174084048733&pagename=Agriculture-Main%2FCDAGLayout