Dames Rocket

Common Name: Dames rocket
Scientific Name: Hesperis matronalis
Origin: Eurasia

Description

Dames rocket is a flowering biennial that was introduced in North America in the 1600s. During its first year, it grows as a basal rosette. In its second year, its flowering stem grows up to 4 ft. tall. Dames rocket has alternate, lance-shaped leaves with serrate margins. It flowers from May through July, producing clusters of flowers that vary in color from purple to white. It is similar in appearance to the native summer phlox. However, phlox have 5-petaled flowers while dames rockets have 4 petals.

Habitat

Dames rocket grows in disturbed areas, woodlands, roadsides and meadows. It prefers partial sun and moist soils. It has now been introduced in all northern parts of the United States.

Threat

Dames rocket is sold in nurseries and its seeds are included in “wildflower” mixes. Its use as an ornamental is likely how it spread throughout North America. This plant grows very aggressively, by producing large amount of seeds and shading out native vegetation.

Management

Dames rocket can be managed by cutting off the flower heads and disposing of them in landfill-bound garbage bags, to ensure that they do not produce seed. However, as a perennial, this won’t reduce the current infestation. This plant can also be treated with herbicides. An ideal time to use herbicides is in the early spring or late fall, when most native plants are dormant, because the rosettes of dames rocket stay green year round. Smaller populations can be hand-pulled.

Regional Distribution

Widespread

WNY PRISM Priority

Tier 4 – Local Control

Invasive Species Priorities – Tier Chart