Sweet rocket (dame’s violet) Hesperis matronalis
Sweet rocket (dame’s violet) (Hesperis matronalis) is a biennial flowering plant in the Brassicaceae family, native to Southern and central Europe to western Asia. It grows 60 cm–1.2 m (24 in–3.9 ft) tall and 35–50 cm (14–20 in) wide, wants part sun to part shade and moderate water, and is hardy to about -30 °C (-22 °F). Space plants about 40 cm (16 in) apart.
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Sweet rocket (dame’s violet) at a glance
| Type | Biennial flowering plant |
|---|---|
| Family | Brassicaceae |
| Mature height | 60 cm–1.2 m (24 in–3.9 ft) |
| Mature spread | 35–50 cm (14–20 in) |
| Spacing | 40 cm (16 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 6–8 |
| Cold hardiness | About -30 °C (-22 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Flowering | about 43–57 weeks after planting, for 5–9 weeks |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Southern and central Europe to western Asia |
| Common in gardens of | 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇫🇷 France, 🇩🇪 Germany, 🇵🇱 Poland, 🇷🇺 Russia, 🇹🇷 Turkey, 🇺🇸 United States, 🇨🇦 Canada |
| Invasive in | parts of the USA and Canada (spreading into woodland edges): check local rules before planting |
Is Sweet rocket (dame’s violet) toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not known to be poisonous to people or pets.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Sweet rocket (dame’s violet)
Good neighbours
- good With Rhubarb: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Evidence D
- good With Nasturtium: Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas. Evidence C
Questions about Sweet rocket (dame’s violet)
- How far apart should I plant Sweet rocket (dame’s violet)?
- About 40 cm (16 in) apart, centre to centre. A mature plant spreads 35–50 cm (14–20 in).
- Does Sweet rocket (dame’s violet) need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Sweet rocket (dame’s violet) need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Sweet rocket (dame’s violet)?
- It tolerates about -30 °C (-22 °F) once established, roughly USDA zone 4. As a biennial it is usually planted out after the last frost and flowers in its second year.
- When does Sweet rocket (dame’s violet) flower?
- About 43–57 weeks after planting, for 5–9 weeks.
- Is Sweet rocket (dame’s violet) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not known to be poisonous to people or pets.
- What grows well with Sweet rocket (dame’s violet)?
- Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
- USDA PLANTS Database, USDA NRCS
- CABI Invasive Species Compendium, CABI
Notes and assumptions
- A biennial or short-lived perennial that seeds itself. Purple or white flowers, strongly scented in the evening, draw moths. Often mistaken for phlox, which has five petals; this has four.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Broccoli Brassica oleracea var. italica
- Cauliflower Brassica oleracea var. botrytis
- Cabbage Brassica oleracea var. capitata
- Kale Brassica oleracea var. sabellica
- Radish Raphanus sativus
- Bok choy Brassica rapa subsp. chinensis
- Brussels sprout Brassica oleracea var. gemmifera
- Kohlrabi Brassica oleracea var. gongylodes