Oxeye Daisy 
(Chrysanthemum leucanthemum)

County Management Strategy: Suppression above approximately 7,000 feet elevation. Eradication below approximately 7,000 feet elevation.

Identification: A perennial, white flowered daisy with creeping roots growing to 2 feet tall. Leaves have toothed edges and are 2-5 inches long, getting smaller toward the top of the plant. The flowers are 1½ inches in diameter and borne singly on the ends of branches. The yellow disk of the flower has a round depression in the middle.

Other names: marguerite

Similar Species: Shasta daisy is a common ornamental daisy with larger leaves and flowers. Two noxious weeds, scentless and Mayweed chamomile have fern-like leaves and have flowers with an inflated disk (central part of the flower).

Control Timing: In the spring before flowers appear and in the fall.

Control target: Prevent seed production and stress root system.

Control Methods: Herbicides have been shown to be the most effective control method. Mechanical removal may stimulate shoot production from the rhizomatous roots. No biocontrol agents are available for this weed.

Status in Mesa County: Fairly common in pastures in higher elevations of eastern Mesa County, and in some flowerbeds in lower elevations. Oxeye daisy may still be found for sale as seed, in wildflower seed mixes, or as bedding plants. It is illegal to sell this species in Colorado. Report seed sales to the Colorado Department of Agriculture Conservation Services Department.

Photos:
http://www.agf.gov.bc.ca/cropprot/weedguid/oxeyed.htm

Fact sheets and control:
http://www.mtweed.org/Identification/oxeye_daisy/oxeye_daisy.html

Additional Links:
http://www.invasive.org/browse/subject.cfm?sub=5937