CultivaOS
Herbarium
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Rhubarb

Rheum × hybridum

Leafy

Rhubarb is a vigorous, low-maintenance perennial grown for its tart, pink or red stems, typically harvested from March to July. It is one of the most reliable crops for UK gardens, tolerating hard frost and poor conditions once established. Forced rhubarb - produced by covering crowns with a pot in February - yields earlier, sweeter, more tender stalks and is a traditional British delicacy.

Key facts

Family
Polygonaceae
Category
Leafy
Sowing window
Feb–Mar, Oct–Nov
Sowing depth
50 mm
Watering
medium
Frost sensitivity
low
Days to maturity
Ready from year 2; light harvest only in year 1
Harvest window
Mar - Jul

Sowing notes

  • -Plant crowns October-November or February-March
  • -Do not harvest leaves - they are toxic
  • -Light harvest only in year 1 - allow plant to establish
  • -Force early sweet stalks by covering with a pot or forcing jar in February
  • -Leave plants to recover from July onwards - do not harvest late in the season

Varieties

Issues & threats

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Wilting

Environmental

Plants are drooping or losing vigour. Most commonly caused by water stress but can also indicate root damage, vascular disease, or heat scorch. Identifying the cause quickly is important as some causes are serious.

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Poor germination

Environmental

Seeds are emerging unevenly or not at all. Usually caused by soil temperature being too low, seeds sown too deep, poor seed-to-soil contact, or old seed stock.

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Damping off

Fungal disease

Pythium spp. / Phytophthora spp.

Young seedlings collapse at or just below soil level, caused by fungal pathogens that thrive in overwatered, poorly ventilated growing conditions. Can spread rapidly through a seed tray.

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Yellowing leaves

Environmental

Leaves are turning yellow, which can indicate a range of problems including nutrient deficiency, overwatering, disease, or natural senescence. Identifying whether the pattern is upper or lower leaves, whole leaves or between veins, is key to diagnosis.

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Stunted growth

Environmental

Plants are significantly smaller or slower to develop than expected. May be caused by poor soil, nutrient deficiency, root restriction, compaction, pest damage to roots, or disease.

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Chewing damage

Pest

General chewing damage from an unidentified pest, leaving holes or missing leaf sections. May be caused by caterpillars, beetles, or other insects. Inspect at dusk to identify the culprit.

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Sap-sucking pests

Pest

General sap-feeding pest activity causing weakened or distorted growth. May be caused by aphids, whitefly, scale insects, or other sucking insects. Inspect leaf undersides and growing tips to identify the pest.