From May to July, the roadsides in my area are often graced with pinkish, purple, and white clusters of flowers. The showy display is a sure sign of the coming summer. The dame’s rocket (Hesperis matronalis) is responsible for these splashes of color.Dame’s rocket is a biennial typically blooming once in its second year. A member of the mustard family, it is native to Eurasia and is invasive throughout much of northern North America–often spread by humans through seed packets. Toothed, lanceolate leaves are alternately arranged on the stem–both stem and leaves with short hairs. The flower clusters consist of many four-petaled flowers–typical of other mustard relatives. Flowers range from purple to pinkish to white with some plants showing a mix of two colors. The fruits are thin, stem-like capsules and seeds set from May to August.
Dame’s rocket grows in partial sun on disturbed sites–roadsides and abandoned lots–and moist woodlands. Dame’s rocket can be mistaken for native phlox species, which have five petals, opposite leaves with no teeth, and rounded fruits.
Despite its pleasant bouquets, dame’s rocket is listed as an invasive weed in Canada and the continental United States. Massachusetts and Connecticut have banned or prohibited the plant from sale and many areas are attempting to eradicate dame’s rocket invasions.