Hesperis matronalis aka Dame's Violet

Hesperis matronalis is also known as dame's rocket. It belongs to the mustard family. Its native range spans southern France, Slovakia, and the Caucasus. It is a biennial or short-lived perennial. Plants that escaped gardens now grow across much of North America. They grow in open woods, prairies, roadsides, and disturbed ground. Their many seeds can help them crowd out native plants. Some United States regions list the plant as invasive or noxious.

Plants grow upright, with one stem or several branches. Garden plants reach 2–3 feet [0.61–0.91 metres] tall. Some reach 4 feet [1.22 metres]. Spread can reach about 2 feet [0.61 metres]. Fine hairs coat the greenish-gray stems. The base may turn woody with age. In their first year, plants form a low rosette, or ring of leaves. They have no flowers at this stage. Later leaves grow in turn along the stems. Their edges have teeth. Their shape ranges from oval to lance-shaped. Leaves grow smaller near the stem tips.

Loose flower clusters, called racemes, bear white, lavender, or purple blooms. Each flower has four petals. It measures about half an inch across. Plants bloom in April and May, sometimes into early summer. Their clove-like scent grows stronger as evening comes. Butterflies and moths visit the flowers. Long, narrow seed pods follow the blooms. These pods, called siliques, hold many seeds and help plants spread. The flowers also suit cutting to display indoors.

Grow it in sun or partial shade. Give it moist soil that drains well. Partial shade suits places with hot summers. It accepts chalk, clay, loam, and sand. Neutral or alkaline soil suits it well. Sources rate it hardy in USDA zones 3–8 and RHS H6. Plants grow fast and take hold from seed. Remove spent flowers, and plants may bloom again. Older plants flower less. New seedlings can renew a planting. Leaves may fade after bloom and leave gaps in borders.

Its scent and blooms suit cottage gardens and meadows. Yet its spread makes it a poor landscape choice where invasive. Serious pests and disease rarely cause trouble. Cabbage caterpillars and flea beetles can still cause harm. So can slugs and snails. Powdery mildew and viruses may also occur. Young leaves supply vitamin C. They taste a little bitter in salads. Sprouted seeds are also edible. Past uses include leaves for scurvy and to cause sweating. People also used leaves to increase urine flow. Seed oil has served as an ingredient in perfume.