Vail Weed of the Week: Dame’s rocket (Hesperis matronalis)
Eagle County Weed of the Week
Vail, CO Colorado
For years, this plant was included in “wildflower” seed mixes. It is currently in bloom and can be found throughout Eagle County in home landscapes and native areas. This plant is targeted by Eagle County’s municipal and county noxious-weed-management programs.
• Biennial or short-lived perennial growing as high as 3 feet.
• Flowers are typically pinkish-purple to white with four petals, clustered in loose stalks at the tops of the stems.
• Leaves are lance shaped with fine-toothed margins.
• Has a shallow root system and reproduces by the large number of seeds that it produces.
• Prefers moist soils and shaded areas.
• Can be confused with our native fireweed. However, dame’s rocket blooms from the top down in the spring, while fireweed blooms from the bottom up in the late summer into fall.
• Dame’s rocket can be controlled by hand-pulling the plant before it flowers or produces seed. Be sure to remove the flowers of dame’s rocket before they set seed, and always dispose of plants in a plastic bag to prevent further spread.
• These measures must be repeated for several years to manage an infestation because dame’s rocket is such a prolific seeder.
• Dame’s rocket is very susceptible to powdery mildew (which is a gray, powdery fungus that grows on the leaf surface) and is almost always affected by it in the high country.
If you have this plant in your home landscape, remove it as soon as is practical. There are numerous replacement options including many species of native penstemons (Penstemon species), beebalm (Monarda fistulosa) and columbines (Aquilegea species) that can match its color and form.
For more information on these plants and the weed-management programs in Eagle County, visit http://www.eaglecounty.us/weed or http://www.vailgov.com/weeds. Or call the Eagle County Weed and Pest Department at 970-328-3540, the town of Vail Department of Public Works at 970-479-2158 or the Eagle County Extension Office at 970-328-8630.