Well-Known and/or Old Weeds (Dirty Dozen)

A list of well-known or old weeds, commonly known as Dirty Dozen, was also produced. These species had established in the northwestern United States by the 1930's and are well described in the weed management literature. It is comprised of:

(1) Category 2 or 3 noxious weeds in Montana that have been reported in the past in the project area, but that are presently not widespread, or, are believed to have been eradicated: these species have high potential to become significant problem plants unless new occurrences are detected early and eradicated, and

(2) well-known weeds that are relatively common but not presently noxious in Montana.  Some of these latter species may be declared noxious in the future.

Note: The "more info" column has the following links: 
   - distribution data for the five northwestern states (executes a query on the INVADERS Database) 
   - a list of related links on the web
    - view the list of states/provinces where this weed is declared noxious
 
 

Species	Common name	Noxious status listing in continental US states and Canadian provinces	More  info
Artemisia absinthium	absinth wormwood
Centaurea solstitialis	yellow starthistle
Chondrilla juncea	rush skeletonweed
Chrysanthemum leucanthemum	oxeye daisy
Conium maculatum	poison hemlock
Cynoglossum officinale	houndstongue
Cytisus scoparius	scotch broom
Dipsacus fullonum	common teasel
Isatis tinctoria	dyer's woad
Lythrum salicaria	purple loosestrife
Senecio jacobaea	tansy ragwort
Tanacetum vulgare	common tansy