Dame's Rocket – Give This Lady a Miss
Dame's rocket (Hesperis matronalis) is often confused with phlox by admirers who assume, because of its widespread abundance, that it is a North American native wildflower. Its bright and fragrant lavender, purple, pink, or white flowers appear in Pennsylvania, usually from mid to late spring, with occasional blooms continuing into late summer. Frequently found in open fields, wetlands, disturbed areas, forest edges, and lightly shaded woodlands, it prefers to grow in moist soil and light shade, but is adaptable to a wide range of growing conditions.
Dame's rocket is not native, however. It was introduced to North America by early settlers from Europe, who grew it in their gardens for culinary uses as well as for its fragrance, beauty, and easy maintenance. Since then, it has escaped cultivation and naturalized over much of the northern half of the United States and into Canada. It is originally native to southern Europe, extending across the Mediterranean region into parts of Asia, and has also naturalized in much of the rest of Europe.
Dame's rocket is not a phlox, either, and it has some distinctive traits that class it as a member of the mustard or cabbage family (Brassicaceae). Each individual flower, clustered in a raceme (spike-like) inflorescence, has four petals arranged as a cross. The older name of the mustard family, Cruciferae, which means "cross-bearers," alludes to this family trait of cruciform petals. Phlox flowers, in contrast, have five petals. The coarse, lance-shaped leaves of dame's rocket are arranged alternately (one leaf at each node) along the upright stems, whereas phlox leaves are arranged oppositely (two leaves set across from each other at each node) along the stems.
The common name, dame's rocket, and its scientific name, Hesperis matronalis, offer more clues about its origins and characteristics. Dame's rocket is just one of the many common names bestowed on this plant; others include dame's violet, damask violet, sweet rocket, queen's gilliflower, and mother-of-the-evening. Rocket is a common name often associated with species in the mustard family (for instance, yellow rocket), from the French word "roquette." Dame's and damask are anglicized from the French word "damas," alluding to Damascus, in Syria. The name of the genus, Hesperis, means "evening" in Greek, a nod to its heady fragrance at dusk; and the specific epithet, matronalis, refers to an ancient Roman festival, the Matronalia, which took place in early March to honor matrons – older married women. In the more southerly regions of its origin, dame's rocket begins to bloom during that early spring period, several weeks before its flowers first appear in more northern climates.
Dame's rocket is also a prolific seed producer, which has aided in its escape from gardens and rapid spread into uncultivated ground. The seedpod is a long, narrow capsule, called a silique, which holds many seeds in two rows. The silique is held shut along suture lines, which split open (in botanical parlance, dehisce) when the seeds are ripe and ready to disperse. This type of dehiscent seedpod is also a trait of species in the mustard family, although the shape of the capsule may vary, from the circular translucent pod of the money plant (Lunaria annua), whose flowers look very similar to those of dame's rocket, to the heart-shaped "purse" of shepherd's-purse (Capsella bursa-pastoris).
Dame's rocket usually grows as a biennial, two to four feet in height, producing a rosette of basal foliage in the first year; after it has produced flowering stalks and set seed during its second year, the plant dies. Occasionally, though, plants will survive a few more years as a short-lived perennial, particularly in a garden setting where the gardener may deadhead old flower heads to encourage a new flush of flowers.
Despite its short life span, its prolific seed production and adaptability to just about any growing site has enabled dame's rocket to spread its seed far and wide. For those same reasons, its seed is frequently included in so-called native wildflower seed mixes, often touted to gardeners as a quick and easy method to create a pollinator-friendly meadow. As a result, dame's rocket has become not only naturalized but even invasive in some states, forming thick stands that crowd out native forbs (herbaceous flowering plants other than grasses). If you are looking at wildflower seed mixes, check the listed species carefully to avoid adding this aggressive spreader to your garden and surrounding landscapes.
In Pennsylvania, the Department of Conservation and Natural Resources (DCNR) includes dame's rocket on its Invasive Plant List as a significant threat to native ecosystems. This list is not regulatory, but it does offer guidance to gardeners when considering plant choices. In some states, including Connecticut, Massachusetts, Colorado, and Wisconsin, dame's rocket is regulated as a noxious, restricted, or banned weed due to its invasiveness.
Although dame's rocket is an eye-catching, fragrant flower for the spring garden, it should be grown with full awareness of its invasive tendencies. If you do choose to include it in your garden, deadhead it as soon as the flowers fade, before it goes to seed. If it begins to spread, dig or pull unwanted plants while still small in their first year, which is easier to do when the soil is moist; just be sure to get the entire taproot to prevent resprouting.
Better yet, perhaps, to give this lady a miss; instead, choose some lovely native alternatives, of which there are many. Carolina phlox (Phlox carolina), meadow phlox (P. maculata), summer phlox (P. paniculata), and prairie phlox (P. pilosa) are four North American native species that are similar in appearance and habit to dame's rocket, but longer-lived and much better behaved. Other species native to North America that can fill in for dame’s rocket include bluestar (Amsonia tabernaemontana, A. hubrichtii), columbine (Aquilegia canadensis), false indigo (Baptisia alba, B. australis), wild geranium (Geranium maculatum), beardtongue (Penstemon digitalis, P. hirsutus), Jacob's ladder (Polemonium reptans), catchfly (Silene caroliniana, S. virginica), and spiderwort (Tradescantia virginiana).
