Rhubarb
Rheum × hybridum
Before you grow or eat this
Rhubarb LEAVES are toxic and must never be eaten. They contain oxalic acid and other compounds at levels that have caused serious poisoning, and cooking does not make them safe. The leaf stalks — the part that is eaten — are perfectly safe. Cut the leaf off and compost it as soon as you pull a stalk, so there is never a leaf in the kitchen. Keep pulled leaves away from children and grazing animals.
A long-lived perennial crown that produces the first pickings of the year, needs almost nothing, and carries one genuinely important safety fact: the leaves are toxic and the stalks are not. Plant it once, feed it generously, divide it every five or six years, and it will outlast most things in the garden.
- Position
- Full sun or Partial shade
- Water
- moderate demand
- Drainage
- Moisture-retentive
- Grows to
- 60–100 cm × 100–150 cm
- Hardiness
- H7
- Harvest
- April to March
- Difficulty
- Straightforward
Described view
A terracotta forcing pot over a rhubarb crown, with the lid lifted to show pale pink blanched stalks growing inside
August
Nothing to do
No sowing, planting, harvesting or pruning window falls in August.
Rhubarb’s year
Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.
| Activity | J | F | M | A | M | J | J | A | S | O | N | D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Plant | January. | February. | March. | October. | November. | December. | ||||||
| Harvest | February. | March. | April. | May. | June. | July. | ||||||
| Divide | January. | February. | November. | December. | ||||||||
| Dormant | January. | November. | December. |
Names that cause confusion
rhubarb — Not botanically a fruit — the crop is a leaf stalk, making it a vegetable in botanical terms. GrowingHQ files it under fruit because that is how it is grown, cooked, sold and looked for, and says so on the record rather than quietly implying otherwise.
Timing that travels
The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.
Pollination
Whether one plant on its own will set fruit, and what has to be true if it will not.
One plant on its own will crop.
- Self-fertility
- Self-fertile
- Partner needed
- No partner needed
- Pollen moved by
- Insects
Where the pollination figures come from
- Self-fertilitySourced guidancehigh confidence
Academic here — the crop is the leaf stalk, and flowering is something to prevent rather than encourage.
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
- Partner neededSourced guidancehigh confidence
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
- Pollen moved byHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
Rootstocks
No rootstock to choose
A perennial crown, propagated by splitting it with a spade while dormant.
Pruning and training
Every piece of fruit pruning advice follows from one fact: where the plant carries next year's crop.
Fruits on: A perennial crown
There is no woody framework to prune. The plant is managed by dividing, replacing or removing spent growth instead.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
Forms it can be grown as
- Open bush
source
Horticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Annual maintenanceMay, June
Remove flowering stems as they appear, because a crown running to flower diverts its resources out of the stalks that are the crop.
Cut any flower spike out at the base as soon as it is seen. Repeated flowering usually means the crown is old and congested and is asking to be divided.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
What you are committing to
Fruit is a multi-year decision. These are the numbers a nursery label rarely carries.
- First worthwhile crop
- 2–2 years
- Productive life
- 10–20 years
- Propagated by
- Division
- Fruit type
- Perennial stem crop
Where these figures come from
- First worthwhile cropSourced guidancehigh confidence
Nothing is pulled in the first year, and only lightly in the second. Cropping a young crown weakens it permanently.
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
- Productive lifeSourced guidancehigh confidence
Kept going indefinitely by dividing the crown every five or six years.
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
- Propagated bySourced guidancehigh confidence
Split the dormant crown so each piece has at least one visible bud.
- Royal Horticultural Society: Dividing rhubarb
Checked 2026-08-13
Not botanically a fruit
The part eaten is a leaf stalk, which makes this a vegetable in botanical terms. GrowingHQ files it under fruit because that is how it is grown, cooked and looked for — the same reason a botanically fruiting tomato is filed as a vegetable.
source
Horticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
It crops in April when nothing else does, requires no annual work, and forced rhubarb — grown under a cover in the dark — is a delicacy that is expensive and briefly available in shops.
Conditions it needs
- Light
- Full sun, Partial shade
- Direct sun
- 4 hours a day or more
- Frost
- Very hardy
- Hardiness rating
- H7 (RHS)
- Soil
- Loam, Clay, Silt
- Soil pH
- 5.5–7
- Drainage
- Moisture-retentive
- Water needs
- moderate
- Drought
- poor tolerance
- Waterlogging
- moderate tolerance
- Heat
- moderate tolerance
- Wind and exposure
- good tolerance
Where these figures come from
- LightSourced guidancehigh confidence
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
- Direct sunHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- FrostSourced guidancehigh confidence
Needs a cold winter: the dormancy is what produces the strong spring flush.
- Royal Horticultural Society: Rhubarb — hardiness
Checked 2026-08-13
- Hardiness ratingSourced guidancehigh confidence
- Royal Horticultural Society: RHS hardiness ratings
Checked 2026-08-13
- SoilHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Soil pHHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- DrainageHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Water needsHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- DroughtHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- WaterloggingHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- HeatHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Wind and exposureHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
On your soil
Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.
| Soil | Verdict | Why |
|---|---|---|
| Heavy clay | Prefers this soil | Heavy clay suits Rhubarb as it stands: The pH suits it: it wants 5.5 to 7, and this soil is in that range. Clay is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering. There is ample rooting depth for it. |
| Sandy | Works, with one condition | Rhubarb will crop on sandy, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure. |
| Chalky and alkaline | Struggles here | Rhubarb struggles on chalky and alkaline: The soil is substantially too alkaline for it: it wants pH 5.5 to 7, and this soil sits around 7.8 to 8.5. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering. It roots to about 45 cm and this soil offers roughly 40 cm before rock or hardpan. A container or a raised bed of imported soil sidesteps the problem entirely. |
| Loam | Prefers this soil | Loam suits Rhubarb as it stands: The pH suits it: it wants 5.5 to 7, and this soil is in that range. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering. There is ample rooting depth for it. |
| Silty | Prefers this soil | Silty suits Rhubarb as it stands: The pH suits it: it wants 5.5 to 7, and this soil is in that range. Silt is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering. There is ample rooting depth for it. |
| Peaty and acid | Grows well here | Rhubarb grows perfectly well on peaty and acid without special measures, though it is not the soil it would choose. |
| Shallow over rock | Struggles here | Rhubarb struggles on shallow over rock: It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering. It roots to about 45 cm and this soil offers roughly 25 cm before rock or hardpan. A container or a raised bed of imported soil sidesteps the problem entirely. |
| Made ground and urban soil | Works, with one condition | Rhubarb will crop on made ground and urban soil, but one thing has to be dealt with first. It roots to about 45 cm and this soil offers roughly 30 cm before rock or hardpan.Grow it in a deep container or a raised bed. The rooting depth is not something that can be added to the ground. |
Not sure which you have? Four hand tests will settle it.
Space and spacing
- Mature height
- 60–100 cm
- Mature spread
- 100–150 cm
- Rooting depth
- 45–60 cm
- Spacing
- 90–120 cm apart
Where these figures come from
- Mature heightHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Mature spreadHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Rooting depthHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- SpacingSourced guidancehigh confidence
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
In a container
- Minimum volume
- 45 litres or moreHorticultural consensusDepends on conditions
- Minimum depth
- 45 cm
Where the container figures come from
- Minimum volumeHorticultural consensusDepends on conditionsmoderate confidence
Applies when: Possible but rarely satisfactory: rhubarb is a large hungry plant with a deep root system.
No external citation — see the evidence type above.
Checked 2026-08-13
- Minimum depthHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
Where and how you can grow it
Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.
| Method | Suitability | What it needs |
|---|---|---|
| Open ground | Well suitedsourceSourced guidancehigh confidence
Checked 2026-08-13 | A permanent position — it stays for a decade or more |
| Traditional dug bed | Well suitedsourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | |
| Raised bed | WorkablesourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | Takes up a lot of a bed for a long time. |
| Greenhouse | WorkablesourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Polytunnel | WorkablesourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Container | MarginalsourceHorticultural consensusmoderate confidence A large hungry plant with deep roots; rarely as good as in the ground. No external citation — see the evidence type above. Checked 2026-08-13 | |
| Hydroponics | MarginalsourceGrowingHQ editorial positionmoderate confidence A large perennial crown that needs a cold winter to produce its spring flush, and that occupies a square metre for a decade. Every property that makes rhubarb a good garden plant makes it a poor soilless one.
Checked 2026-08-13 | |
| Windowsill | Not suitablesourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 |
Growing it
- HarvestingPull stalks with a twist rather than cutting, taking no more than half the stems at once and stopping altogether by midsummer. The leaves the plant keeps are what build next year's crown.
- FeedingMulch generously with well-rotted manure each winter, keeping it off the crown itself. Rhubarb is a very hungry plant and responds visibly.
- PropagationDivide the crown every five or six years while dormant, keeping at least one bud on each piece. A congested crown produces thin stalks and runs to flower.
- ProtectionFor an early crop, cover a crown with a bucket or forcing pot in midwinter to exclude all light. Force the same crown only every other year — it is an exhausting process for the plant.
Where this guidance comes from
- HarvestingSourced guidancehigh confidence
- Royal Horticultural Society: Harvesting rhubarb
Checked 2026-08-13
- FeedingSourced guidancehigh confidence
- Royal Horticultural Society: Growing rhubarb
Checked 2026-08-13
- PropagationSourced guidancehigh confidence
- Royal Horticultural Society: Dividing rhubarb
Checked 2026-08-13
- ProtectionHorticultural consensusmoderate confidence
- Royal Horticultural Society: Forcing rhubarb
Checked 2026-08-13
Is it worth putting under cover?
Whether it will grow there is on the methods table above. This is whether the space is well spent, which is a different question and usually the one being asked.
| Structure | What protection is worth | What decides it |
|---|---|---|
| Greenhouse | Extends the seasonsourceGrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file.
Checked 2026-08-13 | Crown size and the chilling requirement. A crown needs a hard winter outdoors before it can be forced, so this is a two-place crop rather than a protected one.Forcing is a real and worthwhile use of cover, and it is done to a crown that has already had its cold. Growing rhubarb under glass all year gives thin sticks and a weak crown. |
| Polytunnel | Extends the seasonsourceGrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file.
Checked 2026-08-13 | Crown size and the chilling requirement, on the same terms. |
Growing it without soil
Nearly anything can be grown in a soilless system by somebody with enough equipment. The useful question is whether it is worth it, in which technique, and what goes wrong.
It can be made to grow, but a soilless system is the wrong tool — usually because of rooting volume, running cost, or a result no better than a pot of compost.
source
GrowingHQ editorial positionmoderate confidence
A large perennial crown that needs a cold winter to produce its spring flush, and that occupies a square metre for a decade. Every property that makes rhubarb a good garden plant makes it a poor soilless one.
- GrowingHQ editorial synthesis — GrowingHQ
Checked 2026-08-13
Included as an assessment rather than a suggestion — the answer to 'can I?' is yes, and to 'should I?' is no.
Techniques that suit it
- Ebb and flowA bed of inert medium floods and drains on a timer. The medium holds moisture between floods, which makes it far more tolerant of interruption than NFT.
source
Horticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Root space
- Very large and permanent.
- pH band
- 5.5–6.5
Where these figures come from
- Root spaceHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- pH bandSourced guidancehigh confidence
Outside roughly this band, individual nutrients become unavailable even when they are present in the solution — which is why a crop can starve in a full reservoir.
- Purdue Extension — Purdue University: Hydroponic solution management — pH
Checked 2026-08-13
No nutrient recipes here
GrowingHQ records pH bands, which are measurable properties of nutrient availability, and deliberately records no EC or PPM targets and no mixing instructions. Published targets vary by cultivar, growth stage, water source and technique, and the figures that apply to your system are on the product you bought.
Harvesting
- When it is readyPull when the stalks are a usable length and the leaf has fully opened. Colour depends on the cultivar and is not a ripeness test.
- How to pick itGrip low on the stalk and pull with a twist so it comes away cleanly from the crown. Cutting leaves a stub that rots back into the crown.
- Keeping itA week refrigerated; freezes well.
Where the harvest guidance comes from
- When it is readyHorticultural consensusmoderate confidence
- Royal Horticultural Society: Harvesting rhubarb
Checked 2026-08-13
- How to pick itSourced guidancehigh confidence
- Royal Horticultural Society: Harvesting rhubarb
Checked 2026-08-13
- Keeping itHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
What goes wrong
| Problem | How often | Notes |
|---|---|---|
| Slugs and snails | occasionalsourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | On emerging spring growth. |
What to look for
Views that settle something a description cannot. Where the photograph has not been taken yet, the description of what it will show is here instead — which is the useful half of it either way.
Described view
A rhubarb stalk pulled with a twist showing the clean white base, with the toxic leaf being cut off and set aside
- The stalk is food; the leaf is not. Separate them at the plant.
Safety and edibility
Listed as harmful to cats or dogs
Rhubarb is listed as harmful if eaten. The LEAVES contain soluble oxalate salts, which bind calcium in the bloodstream and can damage the kidneys. Eating them causes drooling, vomiting and tremors. The stalks — the part people eat — are not the hazard, and leaves trimmed off during harvest and left on a compost heap are the realistic exposure route for a dog.source
Sourced guidancehigh confidence
- ASPCA Animal Poison Control Center — toxic and non-toxic plant list — American Society for the Prevention of Cruelty to Animals: Rheum rhabarbarum — toxic plants list
Checked 2026-08-13
Affected parts: leaf.
- ToxicitychildrenpetsRhubarb LEAVES are toxic and must never be eaten. They contain oxalic acid and other compounds at levels that have caused serious poisoning, and cooking does not make them safe. The leaf stalks — the part that is eaten — are perfectly safe.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Potentially harmful garden plants
Checked 2026-08-13
Cut the leaf off and compost it as soon as you pull a stalk, so there is never a leaf in the kitchen. Keep pulled leaves away from children and grazing animals.
Sources for this page
Agriculture and Horticulture Development Board · GrowingHQ editorial synthesis · Royal Horticultural Society
Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-13.
If something is wrong with it
- Plant running up to flower before it is ready to eat — 2 causes GrowingHQ holds for rhubarb
Something else? Work through it with the diagnostic tool.