Rumex hydrolapathum

RHS Plant Profile

water dock

Other common names

great water dock, horse sorrel

Synonyms

Rumex maximus

Aquatic Bogs Herbaceous Perennial

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A tall, fast-growing spreading perennial dock which can reach a height of around 2m, with long, tapered green leaves widely found in damp, boggy places such as the edge of ponds, rivers and canals. Long spikes of pinkish-green flowers appear from July through to September. Leaves are edible with a lemony taste but should not be eaten in large quantity. They also have medicinal properties

Position

Full sun, Partial shade

Soil Types

Chalk, Clay

Max Height

1.5-2.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 1 year
Max Spread: 0.1-0.5 metres
Max Height: 1.5-2.5 metres

Growing Conditions

Chalk Clay

Moisture: Poorly–drained
pH: Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or South–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H4

Botanical Details

Family: Polygonaceae
Native to GB/Ireland: Yes
Foliage: Deciduous
Habit: Clump forming
Potentially harmful: Harmful if eaten in large amounts. Wear gloves and other protective equipment when handling Pets: Harmful if eaten in large amounts - for further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants
Genus: Rumex can be annuals, biennials or perennials with mostly basal, simple leaves and erect panicles or racemes of small greenish or reddish flowers followed by reddish-brown, triangular fruits
Name Status: Correct

How to Grow

Cultivation

Grows best in moist soil or shallow water, avoiding acidic soils. Self-seeds freely and also spreads from the roots so can be difficult to control or eradicate. See the advice page on controlling sheep's sorrel for more details

Propagation

Propagate by seed

Pruning

No pruning required

Pests

May be susceptible to slugs and aphids

Diseases

Generally disease-free