Rhubarb

Sun

Full sun in cool climates; light afternoon shade where summers are warmer.

Water

Keep the root zone evenly moist during active growth, watering deeply during dry spells. Avoid waterlogged soil, especially in winter.

Soil

Deep, fertile, moisture-retentive but well-drained soil, preferably slightly acidic to neutral. Improve heavy soil drainage before planting.

Height

2-3 ft (0.6-0.9 m) in leaf; flower stalks can reach 5-6 ft (1.5-1.8 m)

Spread

3-4 ft (0.9-1.2 m)

Flowers

Small creamy-white to greenish-white flowers in tall, branched clusters in late spring to early summer; usually removed on cropping plants.

Foliage

Large, rounded to broadly heart-shaped green leaves with crinkled surfaces and wavy edges, carried on thick red, pink or green stalks. Stalk colour depends on the cultivar and does not reliably indicate sweetness.

Growth

Moderate; allow two growing seasons before regular harvesting.

Care needed

Medium

• Give each crown 3-4 ft (0.9-1.2 m) of space so mature leaves are not crowded.
• Water deeply during dry weather while leaves are growing; do not leave crowns sitting in wet soil.
• Apply compost or well-rotted manure around the plant in late winter, keeping it clear of the crown.
• Feed in early spring with a balanced garden fertiliser, following the label rate.
• Do not harvest in the first growing season; harvest lightly in the second, then take stalks for about eight weeks each spring, always leaving plenty of leaves.
• Divide congested or declining clumps during dormancy, usually every four to five years.

Pruning. Cut flower stalks off near their base as soon as they appear if you want a good edible crop. After the foliage dies back in autumn, remove dead leaves and stalks without cutting into the crown.

Late winter

Plant dormant crowns or divide established clumps while the soil is workable and not waterlogged.

Early spring

Apply balanced fertiliser and mulch around, but not over, the crown.

Spring

Harvest established plants by gently pulling and twisting full-length stalks from the base; remove and discard the leaf blades.

Late spring

Remove emerging flower stalks and check crowded leaf bases for slugs and snails.

Early summer

Finish harvesting so the remaining leaves can rebuild the crown's reserves.

Summer

Water during dry spells and leave healthy foliage intact.

Late autumn

Clear collapsed foliage and check that winter rain drains away from the crown.

• Place at the back or edge of a vegetable garden, where its permanent crown will not be disturbed by annual digging.
• Use in a potager as a bold foliage contrast to fine-textured herbs and smaller salad crops.
• Plant in an edible mixed border with chives and currants, leaving room for its full leaf spread.
• Repeat clumps along a spacious productive garden boundary to give structure from spring through summer.

Garden styles it suits: Potager (kitchen garden), Cottage garden, Farmhouse, Edible landscape, Homestead and Traditional.

Plant it with: Chives, Strawberries, Redcurrants and Calendula.

Wildlife: Flowers attract bees and other insects if allowed to develop, although flowering is normally discouraged on plants grown for harvest. Dense foliage provides shelter for small garden animals.

• Crown rot: soft, decaying crowns usually indicate poor drainage. Remove badly affected plants and replant healthy stock elsewhere in well-drained soil.
• Slugs and snails: protect emerging shoots by removing hiding places, collecting pests and using labelled iron phosphate bait if needed.
• Leaf spots: remove affected fallen foliage, improve airflow and water the soil rather than the leaves; minor spotting rarely affects the crop.
• Thin stalks or poor growth: stop harvesting, water and feed appropriately, and divide crowded crowns during dormancy. Persistently hot conditions or insufficient winter chill may make the site unsuitable.

The leaves are toxic to people, cats, dogs and horses; their oxalates and other compounds can cause poisoning, including serious kidney injury after substantial ingestion. Do not eat the roots or crown either. The leaf stalks are the edible part and are safe in normal food amounts, but people advised to restrict dietary oxalates should seek medical guidance. Seek urgent medical or veterinary advice after leaf ingestion.

• Greater burdock (Arctium lappa)

  Burdock has leaves with pale, woolly undersides and later produces hooked burrs. Rhubarb has smoother, usually glossy leaf stalks and does not produce burrs; do not identify edible plants by stalk colour alone.

• Giant rhubarb (Gunnera manicata)

  Gunnera is unrelated to edible rhubarb and has much larger, deeply lobed leaves with rough, prickly stalks. It produces dense, cone-like flower spikes rather than rhubarb's airy, branched flower clusters.

Rheum comes from an ancient Greek name for rhubarb, while hybridum indicates the hybrid ancestry of cultivated garden rhubarb.

Propagation. Divide dormant crowns in late autumn or late winter, using a clean, sharp spade or knife. Give each division at least one strong bud and a substantial piece of healthy root. Seed-grown plants vary and do not reliably retain a named cultivar's characteristics.

Accepted botanical name

Rheum hybridum

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.