White (yellow) mustard Sinapis alba
White (yellow) mustard (Sinapis alba) is an annual herb in the Brassicaceae family, native to Mediterranean region. It grows 30–80 cm (12–31 in) tall and 20–40 cm (8–16 in) wide, wants full sun and moderate water, and is hardy to about -4 °C (25 °F). Space plants about 15 cm (6 in) apart.
Plan White (yellow) mustard in your garden →
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White (yellow) mustard at a glance
| Type | Annual herb |
|---|---|
| Family | Brassicaceae |
| Mature height | 30–80 cm (12–31 in) |
| Mature spread | 20–40 cm (8–16 in) |
| Spacing | 15 cm (6 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance none |
| Soil pH | 6–8 |
| Cold hardiness | About -4 °C (25 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 30 °C (86 °F) |
| Flowering | about 5–7 weeks after planting, for 3–5 weeks |
| Days to maturity | About 90 days from planting |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Yes: seeds (mild mustard), seedlings ("mustard and cress"), young leaves |
| Native to | Mediterranean region |
| Common in gardens of | 🇨🇦 Canada, 🇬🇧 United Kingdom, 🇩🇪 Germany, 🇫🇷 France, 🇳🇱 Netherlands, 🇵🇱 Poland, 🇺🇸 United States, 🇷🇺 Russia |
Is White (yellow) mustard toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: seeds
Mustard oils irritate the gut in large amounts.
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 White (yellow) mustard
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 White (yellow) mustard
- How far apart should I plant White (yellow) mustard?
- About 15 cm (6 in) apart, centre to centre. A mature plant spreads 20–40 cm (8–16 in).
- Does White (yellow) mustard need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does White (yellow) mustard need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is White (yellow) mustard?
- It tolerates about -4 °C (25 °F) once established, roughly USDA zone 9. As an annual it is usually planted out after the last frost.
- When does White (yellow) mustard flower?
- About 5–7 weeks after planting, for 3–5 weeks.
- Is White (yellow) mustard poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people mildly toxic. Mustard oils irritate the gut in large amounts.
- What grows well with White (yellow) mustard?
- 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 B (B: extension service or peer-reviewed).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- GRIN-Global Taxonomy, USDA ARS
- EcoCrop crop environmental requirements, FAO
Notes and assumptions
- The main seed in American yellow mustard and English mustard powder; also sown as a quick green manure, dug in before it flowers. Hairy, beaked pods.
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