Rhubarb
Rheum rhabarbarum
Bold-leaved perennial — its leaves are folk medicine for brassicas.
Spacing & sowing
- Plant spacing
- 2 ft 11 in
- In-row spacing
- 2 ft 7 in
- Between rows
- 3 ft 3 in
- Square-foot density
- Not suited to SFG
Calendar (from your frost dates)
- Plant out
- at the last spring frost
- First harvest
- 30 days after the last spring frost
- Harvest ends
- 90 days before the first fall frost
Growing
- Type
- Fruit · Perennial
- Botanical family
- Mixed / other
- Sunlight
- Full sun to part shade
- Watering
- Moderate–high
- Soil
- Deep, rich, moist
- Feeding
- A heavy mulch of manure in late winter.
- USDA zones
- 3a–8a
- Frost tolerant
- Yes
- Pruning
- Take out the flower stalks as soon as they show, and clear the spent leaves in autumn.
Through the year
- Mar–Apr Spring Growth
- Apr–Jul Harvest
- Jul–Oct Growing
- Oct–Dec Leaf Fall
- Jan–Mar Leaf Fall
Harvest
- When
- April to midsummer (forced stems as early as February). Do not harvest at all in the first year after planting; take a light picking in year 2 and full harvests from year 3. Stop pulling by late June/early July so the crown can rebuild — later stems are also stringy and higher in oxalic acid.
- What to look for
- Stems 25–45cm long, thick as a finger or better, with the leaf fully opened. Color is variety-dependent, not a ripeness cue — some are green when perfect. Thin, weak stems mean the crown needs a rest.
- How to harvest
- Pull, don't cut: grip low, twist and pull sideways so the stem comes cleanly from the base — cut stumps rot back into the crown. Take no more than a third to half of the stems at any pick. Cut off and compost the leaves immediately: they are toxic (oxalic acid) and must never be eaten.
- How often
- Every week or two through spring; the plant re-sends stems continuously until you stop at midsummer.
- Storing the crop
- Stems keep a week or two in the fridge (stand in a little water or bag loosely). Chops and freezes raw with no blanching needed. Classic for crumbles, compote, jam, and cordial. Remember: only the stalks are edible.
Companions
Garlic, Onions, Beans
Pests & problems
Garden allies
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Beneficial nematodes Steinernema & Heterorhabditis spp.Hunts Slugs & snails
Microscopic worms watered onto damp soil that hunt down soil-dwelling grubs and release a bacterium that kills them within days. Timing is the whole thing: warm, damp soil and a small target grub, which means late summer for most of what they are used against.
- Centipedes ChilopodaHunts Slugs & snails
Flat, fast, one pair of legs to a segment — and a predator, unlike the slow round millipede it is constantly confused with. It hunts slugs, cutworms, springtails and woodlice by night under mulch and stones. Learn the difference and leave this one alone.
- Frogs & toads AnuraHunts Slugs & snails
A resident toad works the beds every night for slugs, cutworms, and weevils. Recruit them with water — even a sunken basin pond — plus damp shade and an upturned-pot toad house; skip the slug pellets that poison their prey.
- Garden birds PasseriformesHunts Slugs & snails
Both things are true: birds strip your currants and a brood of blue tits takes several thousand caterpillars out of one fruit tree in a fortnight. Net what you must and welcome them everywhere else — a nest box near the apples is worth more than a spray.
- Ground beetle CarabidaeHunts Slugs & snails
Fast, glossy night hunters that patrol the soil surface for slugs, cutworms, and root-fly larvae. Give them daytime cover — thick perennial edges, stepping stones, a log — and skip the tillage that wrecks their burrows.
- Hedgehog Erinaceus europaeusHunts Slugs & snails
A European animal, and worth saying so plainly: there are no hedgehogs in North America, and the ally that does the same night shift here is the toad, the opossum or the ground beetle. Where they do occur, cut a gap in the fence and skip the pellets.
- Rove beetle StaphylinidaeHunts Slugs & snails
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
- Salamanders & newts CaudataHunts Slugs & snails
Damp-loving hunters of slugs, worms, woodlice and beetle larvae that spend the day under a log or a stone and work the beds at night. Companions to the toads: they want the same damp shade, the same log pile, and the same absence of slug pellets.
- Snakes & lizards Colubridae & PhrynosomatidaeHunts Slugs & snails
A garter snake works the beds for slugs and voles and a fence lizard clears grasshoppers off a sunny wall. Almost every snake a gardener meets is harmless and useful; give them a log pile, a warm flat stone and a bit of cover and they stay.
Did you know?
The stalks are food but the leaves are poisonous — they're high in oxalic acid.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com