Dame's Rocket

Hesperis matronalis

What is it?

Dames rocket (Hesperis matronalis) is a former biennial or short-lived perennial ornamental, but is now a designated noxious weed in Colorado. It is often found in ditches, woodlands, gardens and pastures.

Why is it a problem?

This plant is a member of the Mustard Family and can be identified by its numerous purple, pink or white flowers with four petals, grouped together on terminal stalks. The flowers develop in May. Dames rockets grow between 1.5 to 3 feet tall with shallow roots. It has alternatively arranged hairy leaves with toothed margins that grow smaller as they ascend the stem.

The success of this invasive weed is due to the wide distribution of wildflower seed mixes, which are prohibited by law to be sold. This flower is very attractive and therefore, has created a market for seed sales and is sold as a “native” species. However, due to the plants profuse density, it quickly eliminates native species.

Management techniques:

There are various ways in which this noxious weed can be managed:

Establishing selected, aggressive grasses in the area

Mechanical such as pulling or cutting flower stalks and herbicides.
There are no biological control methods at this time. (Weld County)

What can we do?

Do not purchase or plant this species. If found in your garden or land, hand pull or dig up using a spade. Ensure the entire root system is pulled or dug as re-sprouting may occur. Herbicides can be used to kill the whole plant, including the roots. Lastly, plant native alternatives instead of this invasive species. Further, do not compost the pulled plants.

Entities working on this invasive in the Gunnison Basin:

Dames Rocket is included in the BLM and Noxious Weed Plan. A hard copy can be reviewed at the BLM Gunnison Field Office located at 210 West Spencer Street, Gunnison, CO 81230.

General Information on Dame’s Rocket:

Bureau of Land Management

PDF of a noxious weed management plan for natural gas facilities near Montrose

US Forest Service

PDF, description and control of dame’s rocket

National Park Service

Website with general biology of dame’s rocket

Colorado Department of Agriculture

PDF on dame’s rocket identification and management

Colorado Weed Management Association

Website that provides identification, biology & control of dame’s rocket

Weld County

PDF, rangeland and pasture recommendations for controlling dame’s rocket