Dame’s Rocket

Dame’s rocket is a biennial or short-lived perennial forb in the Brassicaceae (mustard) family. It grows from a taproot to form a basal rosette in its first year; in subsequent years it produces an erect stem that reaches 2 to 4 feet tall. Stems may be branched near the top. Basal leaves are elongated, toothed, and have fine hairs. Stem leaves occur alternately on the stem, have fine hairs, and arise directly from the stem without petioles.. All leaves have a prominent light green midvein. Dame’s rocket flowers from late spring to early summer. Flowers occur in showy, loose clusters at the end of branches. Individual flowers are ¾ to 1 inch across, have four petals, and are usually purple, but may be pink or white. Seeds are formed in elongated pods (2 to 5 inches long) which split lengthwise when mature. Stalks with dehisced seed pods may remain late into the season after the plant has died or entered dormancy.

Dame’s rocket is native to Europe. This species was intentionally introduced to North America as an ornamental in the early European colonies. It creates dense infestations by scattering seeds. It is frequently found near residential developments where seeds were once intentionally dispersed and spread out of landscaping. Dame’s rocket can also be found in a variety of habitats including riparian areas, disturbed sites, and rangeland.

Prevention and cultural control strategies should be utilized as much as possible.

There are not any biological controls for dame’s rocket currently available.

Because dame’s rocket has a taproot, it can be readily managed by hand pulling or digging out the root. Repeated mowing after bolting and before seed production can prevent seed production; mowing two weeks after an herbicide application is particularly effective at killing the root and preventing seed production. Do not mow while seeds are present. Clipping flowerheads prevents seed production. Clipped flowers may be utilized as cut flowers, but be sure to dispose of flowers and seeds in a garbage bag.

Larger infestations can be controlled with herbicides. Spring treatments of rosettes or early bolting plants are recommended.

• Management of Invasive Plants in Wisconsin: Dame’s Rocket (Hesperis matronalis). Panke, B. and Renz, M. (2012) University of Wisconsin Cooperative Extension.
• Maine Invasive Plants Field Guide: Dame’s Rocket. Olmstead, N. and Yurlina, M. (2019) Maine Department of Agriculture, Conservation and Forestry: Natural Areas Program.
• Rangeland-Pasture Recommendations: Dames Rocket Identification and Management. Weld County Weed Management.
• Plant Invaders of Mid-Atlantic Natural Areas 4th Ed.: Dame’s Rocket. Swearingen, J., Slattery, B., Reshetiloff, K. and Zwicker, S. (2010) National Park Service and United States Fish and Wildlife Service. Via Invasive.org