Docks

Docks (Rumex spp.) are easily recognised with their large leaves and distinctive seedheads. These leaves are edible and used for herbal remedies and dyeing. They are a common weeds in gardens and difficult to eradicate.

Dock

Quick facts

Common and botanical name Broad-leaved dock (Rumex obtusifolius) and curled dock (R. crispus)
Area affected Recently disturbed ground, rough grass, borders and lawns
Main symptoms Thick tap root that can re-grow and abundant seeds
Timing Leaves appear in spring and seedheads persist into winter; treat spring to autumn

What are docks?

Docks are common throughout the British Isles in recently disturbed land, farmyards, roadsides and gardens. Dock plants support a wide range of insects, including butterflies, moths, plant bugs and beetles. They can be allowed to grow in wilder parts of the garden and flower-rich lawns. Learn more about making the most of lawns as a wildlife habitat and ways to encourage wildlife in the garden;



Boiled dock leaves were used as pig food and fallow deer are particularly fond of the leaves. The leaves have also been used to wrap cheese and butter, hence the name butter-dock. A widespread practise that continues to the present day is to encourage children to use dock leaves to soothe the sting from nettles.

Since dock have a deep tap root which can regrow from the top section and they produce large amounts of seed they can be a troublesome weed in the garden. This page looks at options for the gardener when docks are becoming a problem.

Appearance

Broad-leaved dock (Rumex obtusifolius) is a long lived perennial with a basal rosette of long-stalked, smooth ovate-oblong leaves, stems 80cm-1m (32in-3¼ft) high and the distinctive seedheads on spikes that persist into winter. The tap root can be up to 90cm (3ft) in length.

Curled dock (R. crispus) similar to broad-leaved dock but leaves are tapering with a wavy edge and stems 60cm-1m (2-3¼ft).

The problem

Docks have a thick, branched tap root that can regrow from the top section if damaged.

Seeds are produced in abundance, germinating readily if left on the surface and are capable of surviving in the soil for up to 50 years. Dock seeds are commonly imported via manure however composted manure, municipal compost and other soil improvers should be free of dock seeds.

Curled dock (Rumex crispus) and broad-leaved dock (Rumex obtusifolius) are covered by the Weeds Act 1959 (which specifies five injurious weeds including both curled dock and broad-leafed dock). 

Control

First, consider whether this can be done using non-chemical means such as digging out. Where these methods are not feasible, chemical controls may need to be used.

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.

Cultural control

Docks are difficult for gardeners to control by cultural methods once established.

Try digging isolated specimens out as only the top few inches of rootstock have powers of regeneration and if 12-15cm (5-6in) can be removed, usually there is no regrowth. Docks are especially vulnerable in spring so digging out at this time should be more effective.

Weedkiller control

Grassed areas

Selective weedkillers in lawns:

  • Dock seedlings can be killed by spraying with lawn weedkillers based on 2,4-D or MCPA (Vitax LawnClear 2 or Weedol Lawn Weedkiller), but they become fairly resistant to these weedkillers once they have established a fleshy rootstock
  • Lawn weedkillers based on mecoprop-P may check the growth of docks but not completely kill them
  • Apply lawn weedkillers in late summer after cutting off the flowering heads to prevent seeding, then re-spray leaves that re-grow 14 days after cutting back

Selective weedkillers in rough grassland:

  • Use a selective weedkiller which contains triclopyr (SBK Brushwood Killer) as this would leave the grass unharmed
  • This herbicide is systemic, travelling from the weed foliage down into the root system
  • However as it is non-selective any broad-leaved plants will be damaged (e.g. wildflowers) and so should only be used in grass where such action is acceptable

Non-selective weedkillers:

  • Glyphosate is a more effective treatment for established docks
  • Apply when growing strongly from mid-summer onwards
  • Glyphosate is not selective and any spray coming into contact with grass around the docks would be killed or severely checked
  • Ready-to-use sprays or a gel formulation (Roundup Gel) can make application to individual weeds more accurate

Borders

  • Apply glyphosate as a spot treatment to individual plants or spray areas that have been cleared of cultivated plants
  • Glyphosate is a non-selective weedkiller applied to the foliage, where it is translocated throughout the weed. Tougher formulations are worth trying (e.g. Roundup Ultra, SBM Job done Tough Weedkiller (soluble sachet only), Resolva Pro Xtra Tough or Ecofective Rootblast Super Strength Weedkiller)
  • Being non-selective, it is essential to avoid spray drift onto neighbouring plants. It is important to have good leaf coverage so that as much chemical is absorbed as possible
  • Sprays are most effective if applied from early June to mid-August
  • As this weed is so persistent several applications may be necessary

Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.

Download

Weedkillers for gardeners  (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 1a, b and 4)

Links

Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: using spot and broad-scale
Weeds: non-chemical control

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