Rhubarb Rheum x hybridum
Rhubarb (Rheum x hybridum) is a deciduous perennial vegetable in the Polygonaceae family, native to Garden hybrid; parent species from Asia (Siberia to China). It grows 60 cm–1 m (24 in–3.3 ft) tall and 90 cm–1.2 m (35 in–3.9 ft) wide, wants full sun and moderate water, and is hardy to about -35 °C (-31 °F). Space plants about 90 cm (35 in) apart.
Plan Rhubarb in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Rhubarb at a glance
| Type | Perennial vegetable, deciduous |
|---|---|
| Family | Polygonaceae |
| Mature height | 60 cm–1 m (24 in–3.3 ft) |
| Mature spread | 90 cm–1.2 m (35 in–3.9 ft) |
| Spacing | 90 cm (35 in) centre to centre |
| Sun | Full sun, at least 5 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 6–6.8 |
| Cold hardiness | About -35 °C (-31 °F) once established (roughly USDA zone 3) |
| Heat stress | Likely above about 27 °C (81 °F) |
| Flowering | from about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Low |
| Edible | Yes: leaf stalks (petioles), cooked |
| Native to | Garden hybrid; parent species from Asia (Siberia to China) |
| Common in gardens of | 🇬🇧 United Kingdom, 🇳🇴 Norway, 🇩🇪 Germany, 🇷🇺 Russia, 🇺🇸 United States, 🇨🇦 Canada, 🇸🇪 Sweden, 🇮🇪 Ireland |
Is Rhubarb toxic?
- People: moderately toxic
- Cats: moderately toxic
- Dogs: moderately toxic
- Parts: leaf blades, roots
Leaf blades contain soluble oxalates and anthraquinone glycosides that can harm kidneys and gut; eat only the cooked stalks.
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 Rhubarb
Good neighbours
- good With the Brassicaceae family: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Evidence D
Questions about Rhubarb
- How far apart should I plant Rhubarb?
- About 90 cm (35 in) apart, centre to centre. A mature plant spreads 90 cm–1.2 m (35 in–3.9 ft).
- Does Rhubarb need full sun?
- Full sun: at least 5 hours of direct sun a day.
- How much water does Rhubarb need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Rhubarb?
- It tolerates about -35 °C (-31 °F) once established, roughly USDA zone 3.
- When does Rhubarb flower?
- From about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Rhubarb poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs moderately toxic; for people moderately toxic. Leaf blades contain soluble oxalates and anthraquinone glycosides that can harm kidneys and gut; eat only the cooked stalks.
- What grows well with Rhubarb?
- Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials.
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- RHS Plant Finder, Royal Horticultural Society
- University extension gardening guides (general), Various land-grant university extensions
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- Stalks are not harvested in the first year; flower stalks are normally cut off to keep yield. Hot summers push plants into dormancy.
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
- Sorrel Rumex acetosa
- Vietnamese coriander Persicaria odorata
- California buckwheat Eriogonum fasciculatum
- Buckwheat Fagopyrum esculentum
- French sorrel (buckler-leaf sorrel) Rumex scutatus
- Japanese indigo (ai, dyer’s knotweed) Persicaria tinctoria
- Ornamental rhubarb (Chinese rhubarb) Rheum palmatum
- Himalayan fleeceflower (knotweed groundcover) Bistorta affinis