Persian stone cress Aethionema grandiflorum
Persian stone cress (Aethionema grandiflorum) is an evergreen perennial flowering plant in the Brassicaceae family, native to Rocky slopes of Turkey, Iran, Iraq and the Caucasus. It grows 15–30 cm (6–12 in) tall and 30–45 cm (12–18 in) wide, wants full sun and low water, and is hardy to about -28 °C (-18 °F). Space plants about 30 cm (12 in) apart.
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Persian stone cress at a glance
| Type | Perennial flowering plant, evergreen |
|---|---|
| Family | Brassicaceae |
| Mature height | 15–30 cm (6–12 in) |
| Mature spread | 30–45 cm (12–18 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Full sun, at least 7 h of direct sun a day |
| Water | Low; drought tolerance high, waterlogging tolerance none |
| Soil pH | 6.5–8.5 |
| Cold hardiness | About -28 °C (-18 °F) once established (roughly USDA zone 5) |
| Heat stress | Likely above about 34 °C (93 °F) |
| Flowering | from about May for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Moderate |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Rocky slopes of Turkey, Iran, Iraq and the Caucasus |
| Common in gardens of | 🇬🇧 United Kingdom, 🇩🇪 Germany, 🇺🇸 United States, 🇹🇷 Turkey, 🇮🇷 Iran |
Is Persian stone cress toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not poisonous.
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 Persian stone cress
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 Persian stone cress
- How far apart should I plant Persian stone cress?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–45 cm (12–18 in).
- Does Persian stone cress need full sun?
- Full sun: at least 7 hours of direct sun a day.
- How much water does Persian stone cress need?
- Low water. Drought tolerance is high and waterlogging tolerance none.
- How cold-hardy is Persian stone cress?
- It tolerates about -28 °C (-18 °F) once established, roughly USDA zone 5.
- When does Persian stone cress flower?
- From about May for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Persian stone cress 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 poisonous.
- What grows well with Persian stone cress?
- 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
- Alpine Garden Society Encyclopaedia of Alpines and plant portraits, Alpine Garden Society, Pershore (UK)
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
Notes and assumptions
- A rock-garden plant: give it gritty, very free-draining soil, full light and a collar of gravel around the neck; winter wet kills it far more often than cold.
- A small blue-grey subshrub with clouds of rose-pink, four-petalled flowers in late spring; short-lived but self-seeds into gravel. Thrives in hot, dry, limy soil.
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