Dame's Rocket
Hesperis matronalis
Dame's Rocket (Hesperis matronalis) is an introduced biennial or short-lived perennial of the mustard family, with fragrant, four-petaled flowers in pink to bluish purple or sometimes white, clustered at the tops of hairy stems. Devils Tower National Monument lists it in bloom in May and June, and in South Dakota it grows along roadsides and in thickets and open woods. Photographed in the Black Hills.
| Family | Brassicaceae · Mustard |
|---|---|
| Status | Introduced biennial |
| Blooms | May and June |
| Height | 50–100 cm (20–39 in) |
| Where | Roadsides, thickets, open woods and woodland edges |
Roots, seeds & germination
Seed: Long, thin pods hold a single row of spindle-shaped seeds, 3 to 4 mm long. Flowers keep opening at the top of the stem while seeds ripen below, so pods form all season.
How do you identify Dame's Rocket?
Count the petals. Dame's Rocket has 4, while the native phlox it resembles has 5. Stems are densely hairy, leaves are alternate, sharp-tipped and toothed, and the seed pods are long and thin, 5 to 14 cm.
When does it bloom?
May and June.
Where does it grow?
Roadsides, thickets and open woods throughout South Dakota. It also grows in moist woods, woodland edges, meadows and ditches, and it often colonizes disturbed soil.
Sources: National Park Service, Devils Tower: Wildflowers; SDSU Open PRAIRIE: Hesperis matronalis; Minnesota Wildflowers: Hesperis matronalis (Dame's Rocket); South Dakota DANR: State Noxious Weeds; South Dakota DANR: Locally Noxious Weeds, updated 2024.