Noxious Weeds

Scentless Chamomile
Matricaria perforata, commonly known as Scentless Chamomile, is listed by the State of Colorado as a noxious weed. Originally imported from Europe as an ornamental, this bushy annual has become quite prevalent in Grand County. One plant can produce up to 1 million seeds annually, seeds of which are viable for up to 15 years. This plant invades disturbed soils, continuing to start new plants throughout the growing season.

Eradication is fairly easy as the entire plant can be pulled from the ground by hand. Be sure to wear gloves and dispose of plants carefully as Scentless Chamomile produces a chemical compound which can cause irritation and blistering in some instances.

Oxeye Daisy
Chrysanthemum leucanthemum, commonly known as Oxeye Daisy, is listed by the State of Colorado as a noxious weed. Originally planted as an ornamental in gardens, it has escaped to becoming invasive in our mountain community. Commonly confused with the Shasta Daisy, the Oxeye can be identified by a dimple in the center of the yellow portion of the flower and a faint 'wet dog' smell.

Control requires removal of the plant and the entire root system. The key to keeping them from returning is keeping a healthy native plant community that will shade out the prospective invaders.

Canada Thistle
Cirsium arvense is commonly known as Canada Thistle and is listed by the State of Colorado as a noxious weed.

This aggressive creeping perennial is difficult to control because of its extensive root system and ability to rebound quickly; horizontal roots can extend for up to fifteen feet, and vertical roots may grow 6 to 15 feet deep. This plant is best managed by removing seedlings as they start, but be sure to wear heavy gloves and use a shovel as Canada Thistle has numerous sharp barbs.

For More Information
For more information on noxious weeds and advice on how to create a healthy native plant community, check out the Grand County Division of Natural Resources.