Hesperis matronalis is an herbaceous plant species in the mustard family, Brassicaceae. It has numerous common names, including dame's rocket, damask-violet, dame's-violet, dames-wort, dame's gilliflower, night-scented gilliflower, queen's gilliflower, rogue's gilliflower, summer lilac, sweet rocket, mother-of-the-evening, and winter gilliflower.
These plants are biennials or short-lived perennials, native to Eurasia and cultivated in many other areas of the world for their attractive, spring-blooming flowers. In some of those areas, it has escaped from cultivation and become a weed species. The genus name Hesperis was probably given because the scent of the flowers becomes more conspicuous towards evening.
Hesperis matronalis grows 100 cm or taller, with multiple upright, hairy stems. Typically, the first year of growth produces a mound of foliage, and flowering occurs the second year; the plants are normally biennials, but a number of races can be short-lived perennials. The plants have showy blooms in early to mid spring. The leaves are alternately arranged on upright stems and lanceolate-shaped; they typically have very short or lack petioles and have toothed margins, but sometimes are entire and are widest at the base. The foliage has short hairs on the top and bottom surfaces that give the leaves a somewhat rough feel. The larger leaves are around 12 cm long and over 4 cm wide. In early spring, a thick mound of low-growing foliage is produced; during flowering the lower parts of the stems are generally unbranched and denuded of foliage and the top of the blooming plant might have a few branches that end in inflorescences.
The plentiful, fragrant flowers are produced in large, showy, terminal racemes that can be 30+ cm tall and elongate as the flowers of the inflorescence bloom. When stems have both flowers and fruits, the weight sometimes causes the stems to bend. Each flower is large (2 cm across), with four petals. Flower coloration varies, with different shades of lavender and purple most common, but white, pink, and even some flowers with mixed colors exist in cultivated forms. A few different double-flowered varieties also exist. The four petals are clawed and hairless. The flowers have six stamens in two groups, the four closest to the ovary are longer than the two oppositely positioned. Stigmas are two-lobed. The four sepals are erect and form a mock tube around the claws of the petals and are also colored similarly to the petals.
Some plants may bloom until August, but warm weather greatly shortens the duration on each flower's blooming. Seeds are produced in thin fruits 5–14 cm long pods, containing two rows of seeds separated by a dimple. The fruit are terete and open by way of glabrous valves, constricted between the seeds like a pea pod. Seeds are oblong, 3–4 mm long and 1–1.5 mm wide.
In North America, Hesperis matronalis is often confused with native Phlox species that also have similar large showy flower clusters. They can be distinguished from each other by foliage and flower differences: dame's rocket has alternately arranged leaves and four petals per flower, while phloxes have opposite leaves and five petals.
H. matronalis has been a cultivated species for a long time, and grows best in full sun to partial shade where soils are moist with good drainage. It is undemanding and self-seeds quickly, forming dense stands. Extensive monotypic stands of dame's rocket are visible from great distances; these dense collections of plants have the potential to crowd out native species when growing outside of cultivated areas.
The successful spread of dame's rocket in North America is attributed to its prolific seed production and because the seeds are often included in prepackaged "wildflower seed" mixes sold for "naturalizing". The plants typically produce a low-lying rosette of foliage the first year; in subsequent years, blooming and seed production occurs in tandem throughout the blooming season. This species is commonly found in roadside ditches, dumps and in open woodland settings, where it is noticed when in bloom. Although it makes an attractive, hardy garden plant, it has been found to be ecologically invasive in North America.
H. matronalis is propagated by seeds, but desirable individuals, including the double-flowering forms, are propagated from cuttings or division of the clumps.
- IRELAND: An "escape" to be found in many areas of Ireland, including Belfast. and other areas of Ireland.
- NORTH AMERICA: H. matronalis grows throughout most of the U.S. and Canada. The US Department of Agriculture (USDA) website has a map showing states and provinces in which the plant has been found.
- Colorado: noxious weed (on B-list), with plans for eradication or management varying by area and year
- Connecticut: invasive and banned, e.g. illegal to move, sell, purchase, transplant, cultivate, or distribute
- Massachusetts: prohibited
- Wisconsin: Restricted – an invasive species that is already widely established in the state and causes or has the potential to cause significant environmental or economic harm.
In Alberta, Canada it is considered a noxious weed, meaning its growth or spread needs to be prevented.
Dame's rocket was brought to North America in the 17th century and has since become naturalized there.
In Europe, it is host to the caterpillars of several butterfly species, including the orange tip (Anthocharis cardamines), large white (Pieris brassicae), small white (Pieris rapae), and moths, such as Plutella porrectella.
- "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-01-25. Retrieved 2014-10-17.
- Britton, N. F.; Brown, Addison (1970). An illustrated flora of the northern United States and Canada: from Newfoundland to the parallel of the southern boundary of Virginia, and from the Atlantic Ocean westward to the 102d meridian. New York: Dover Publications. p. 175. ISBN 978-0-486-22643-9.
- "Explore Cornell - Home Gardening - Flower Growing Guides - Growing Guide". www.gardening.cornell.edu.
- "Hesperis matronalis page". www.missouriplants.com.
- "Hesperis matronalis in Flora of China @ efloras.org". www.efloras.org.
- "Help for the Home Gardener". www.mobot.org.
- "Dame's rocket - Wisconsin DNR". dnr.wi.gov.
- Beesley, S. and Wilde, J. (1997). "Urban Flora of Belfast" The Institute of Irish Studies and The Queen's University of Belfast
- Scannell, M. J.P. and Synnott, D.M. (1972). "Census Catalogue of the Flora of Ireland." Dublin: The Stationery Office
- "Plants Profile for Hesperis matronalis (dames rocket)". plants.usda.gov.
- PLANTS Profile for Hesperis matronalis (dame's rocket) | USDA PLANTS
- Edmonton, City of (2018-02-08). "Dame's Rocket". www.edmonton.ca. Retrieved 2018-02-08.
|Wikiversity has bloom time data for Hesperis matronalis on the Bloom Clock|
Media related to Hesperis matronalis at Wikimedia Commons