Dock

Scientific name: Rumex obtusifolius and Rumex species

Broad leaved dock

Curled dock

Broad leaved dock

Fiddle dock leaves

Broad leaved dock seedling

Broad leaved dock flowers

Strong tap root
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

Broadleaved dock (Rumex obtusifolius)

  • Perennial weed with large broad leaves and a thick, strong taproot
  • Up to 1 m tall when flowering at almost any time of the year. Stems erect and leafy with whorls of green to red flowers that later turn brown
  • Leaves broad and flat, heart-shaped at the base.
  • Grow to 35 cm long and 15 cm wide, hairy underneath and with long stalks
  • Fruit are small, heart-shaped, brown, three angled nuts approximately 2.5 mm long
  • Stems become stiff and woody as the plant matures.

Other dock species common in New Zealand:

Curled dock (Rumex crispus)

  • Similar to broad-leaved dock except for its leaves which are narrower, with crinkled edges, leaves tapered towards tip and base. Leaves can be used as a vegetable; roots and seeds may be used for herbal or medicinal purposes
  • Found in similar places to broadleaved dock.

Fiddle dock (Rumex pulcher)

  • Much smaller than either broad-leaved or curled dock with violin shaped leaves
  • Common throughout New Zealand, prevalent under cattle grazing but grazed by sheep.

Origin

  • Native to Europe, docks are now abundant throughout New Zealand
  • Most common in damp waste places and pastures, especially in higher fertility areas such as stockyards, cowsheds, water troughs and gardens.

Life cycle

  • Perennial plant with a strong taproot
  • Flowers at almost any time of the year although flowering does not normally occur within its first year
  • Often stays vegetative throughout winter; leaves stay green and seed stalks often remain standing
  • Regeneration of plant occurs from the taproot, which makes the weed hard to control
  • Mature plants can produce seeds twice during a growing season. Seeds may remain viable in the soil for several years, germinating rapidly after any soil disturbance
  • Birds and wind disperse the seeds.

Benefits

  • Leaves can be used to soothe a range of skin irritations including mosquito bites and nettle rash
  • Leaves may be used in cooking (cream soup and casseroles). and also in salads
  • Roots have been used as a coffee substitute.

Impact on pasture

  • Docks take up large areas of pasture and reduce the productivity and nutritive value of pastures
  • Docks compete well with other pasture species, even when mowed frequently.

Impact on stock

  • Only sheep graze young plants; horses and cows will not. The leaves are, however, high in tannins, which may offer livestock some protection from worms.

Grubbing / mowing of pastures

  • The cheapest and possibly most effective method of control is manual removal of the entire plant using a spade or grubber
  • Using a spade – dig out the plant, ensuring that all of the roots have been removed. If broken pieces of root remain in the soil, they will re-sprout. Dispose of plants and roots by burning or very deep burial
  • Where infestations are large a high cutting frequency for several years reduces the density of plants
  • Frequent topping will stop the plant from seeding and producing seeds; it will also give surrounding pasture the opportunity to compete with dock seedlings
  • A combination of manual removal and herbicides may be required to eradicate this weed.

Chemical control

  • Chemical control of dock is difficult and requires repeat applications for it to be effective
  • The best time to use herbicides is when dock is actively growing (October-December)
  • Dock seedlings are controlled by all phenoxy acetics and phenoxy butyrics and their mixtures.

ALWAYS READ PRODUCT LABELS BEFORE APPLYING

Active ingredient When to apply Residual effect Grass damage Clover damage
aminopyralid Spring Severe No Severe
thifensulfuron-methyl Spring Slight Slight Moderate
dicamba Spring Severe No Severe
glyphosate Spring None Severe Severe but temporary
asulam Spring Slight Slight

Consult your farm consultant, industry rep or the New Zealand Agrichemical Manual for more information about chemical control.

Biocontrol

  • There are currently no biological control agents for dock in New Zealand.

References

  • Pino J, Haggar RJ, Sans FX, Masalles RM 1995. Clonal growth and fragment regeneration of Rumex obtusifolius L. European Weed Research Society 35: 141-148.
  • Popay I, Champion P, James TK 2010: An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.
  • Stilmant D, Bodson B, Vrancken C, Losseau C 2010. Impact of cutting frequency on the vigour of Rumex obtusifolius. Grass and Forage Science 65: 147-153.
  • Young S 2013. New Zealand Novachem agrichemical manual. Agrimedia Ltd, Christchurch, New Zealand. 767 p.
  • Zaller JG 2004. Ecology and non-chemical control of Rumex crispus and R. obtusifolius (Polygonaceae): a review. European Weed Research Society 44: 414-432.