Dame's Rocket is a member of the Mustard Family (Brassicaceae)  This escaped ornamental is beginning to show up in our wildlands. 

This native of Europe may be either a biennial or perennial, and may be from 1-1/2 to 4 feet tall, flowers range in color from white to pink to purple. Dame’s Rocket flowers from April through July. This plant tends to invade riparian and wetland habitat. There are many alternatives to planting Dame’s Rocket including Blue Columbine (Aquilegia caerulea) and Lavender Native Bee Balm (Monarda fistulosa menthaefolia).

This information courtesy of the Colorado Natural Areas Program

Family: Brassicaceae (Mustard)

Other Names: sweet rocket, dame’s violet

USDA Code: HEMA3

Legal Status: Colorado Noxious Weed List B

Growth form: Biennial or short-lived perennial forb.

Flower: Flowers are white or purple with four petals. Flowers are clustered in loose terminal stalks.

Seeds/Fruit: Fruits are many seeded, long and narrow and approximately cylindrical. Seeds are small (3-4 mm long), angular, grooved and dark reddish-brown (Stubbendieck et al. 1995)

Leaves: Leaves are alternate, 2-4 inches long, lance-shaped, with finely toothed margins.

Stems: Mature plants range from 4 inches to 3 feet in height.

Roots: Shallow fibrous root system.

Seedling: No information available.

Agricultural: No information available.

Ecological: Dame’s rocket is commonly planted as an ornamental, but quickly escapes cultivation because of its prolific seed production (Wisconsin DNR 1998). It is thought to be a limited invasive species that will readily invade disturbed ground but is rarely found in undisturbed areas.

General requirements: Dame’s rocket prefers moist soils that have a pH range of 6-7.5. It is commonly found in gardens, partly shaded woodlands, ditches, and other areas that have moist soils and light shade (Perry 1997). Dame’s rocket is often found along roadsides, pastures, rangelands, thickets and open woods.

Distribution: Found throughout the northern United States.

Historical: Dame’s rocket is native to Eurasia and is sold as a garden ornamental. Part of its success can be attributed to its wide distribution in "wildflower" seed mixes (Wisconsin DNR 1998). Dame’s rocket is not widely recognized as an invasive species. Consequently, it may not be recognized as a problem until it is well established (Wisconsin DNR 1998).

Life cycle: Dame’s rocket generally produces a basal rosette the first year, and flowers the following year. The plants are prolific bloomers and produce large quantities of seed from May through July. Individual plants may have several clusters of flowers at various stages of development, enabling the plant to produce both flowers and seeds at the same time (Wisconsin DNR 1998).

Mode of reproduction: Reproduces by seeds.

Seed production: Produces large quantities of seed.

Seed bank: The majority of the seeds will germinate the following year, but some seeds may remain dormant for several years.

Dispersal: No information available.

Locating and removing plants immediately before seed set is the best way to prevent the spread of dame’s rocket. As with other plants which reproduce solely by seed, integrated management efforts must include the elimination of seed production and the depletion of the seed bank. Combine herbicide or mechanical removal of rosettes with removal of seed heads from any plants that have bolted.

Wisconsin DNR. 1998. Dame’s Rocket, (Hesperis matronalis). Exotic species factsheet. Wisconsin Department of Natural Resources. Available: http://www.dnr.state.wi.us/org/land/er/invasive/factsheets/dames.htm

Perry, Leonard.1997. Hesperis matronalis, Plant lecture list for PSS 123. University of Vermont. Internet 2/2/99. Available: http://pss.uvm.edu/pss123/wmhesp.html

Stubbendieck, J., G.Y. Friisoe and M.R. Bolick. 1995. Damesrocket. Weeds of Nebraska and the Great Plains. Nebraska Department of Agriculture, Bureau of Plant Industry, Lincoln, Nebraska. pg. 211.