Oxeye daisy, a member of the Aster family, is a native of Eurasia. It is an erect, rhizomatous perennial plant with white ray and yellow disk flowers, which bloom from June through August. Oxeye daisy is commonly sold in wildflower seed mixes or transplanted as an ornamental despite its tendency to crowd out more desirable vegetation.

Comments: A rapidly spreading weed throughout Pitkin County. Originally planted intentionally in wildflower mixes, this escaped ornamental is found along the Highway 82 corridor between the Castle and Maroon Creek drainages. It is also spreading along Highway 82, Castle Creek, Maroon Creek, Hunter Creek and Independence Pass.

Biological control: None currently available.

Chemical controls: For additional information contact your local city, county or town natural resource office. (See section VII for phone numbers.)

Cultural controls: Careful management of existing vegetation is important to maintain competition for this species.  The seeds of oxeye daisy are small and do not germinate well in existing plant litter but are very opportunistic in open soil. Overgrazing has been shown to enhance the proliferation of this plant.

Mechanical controls: Mowing this species can have positive or negative results depending on the timing of the treatment. Mowing prior to flowering can reduce the production of seed provided follow up mowing occurs to control re-growth. Mowing after seed set will spread seed and provide a disturbance which could enhance the spread of the plant. Tillage is not recommended to control this species due to its rhizomatous growth habit and high seed production which can be exacerbated from soil disturbance and spreading of viable root segments.

Education: The key to oxeye daisy management is to create an awareness among homeowners, nurseries, landscapers, and landscape architects that oxeye is a noxious weed and therefore should not be specified in plantings, sold in nurseries or planted in home gardens or large-scale landscape projects.

Locations of Infestations of Oxeye Daisy on Roads and Open Space in Pitkin County: