Broad-leaved dockBroad-leaved dock

Name: Broad-leaved dock
( broadleaf dock, butter dock, cushy-cows, kettle dock, smair dock )

Latin name: Rumex obtusifolius L.

Occurrence: The two main dock species are the broad-leaved dock (Rumex obtusifolius) and the curled dock (R. crispus). They are common throughout the UK both as the true species and as hybrids. The hybrids may produce less seed but can be more vigorous than the parents and will sometimes infest whole fields. The presence of fertile hybrids has been reported, probably the result of backcrosses with a parent. Broad-leaved dock itself is a highly variable perennial species and many forms, varieties and subspecies have been described worldwide. Three subspecies have been distinguished in the UK.

Broad-leaved dock is found throughout Britain and there is no climatic limitation on distribution. It is the most abundant dock in grassland. Dock seedlings are poor competitors and can only establish in open or disturbed patches in standing vegetation. The presence of docks in grassland is often associated with the uneven application of slurry or manure that leaves bare patches. The openness of a sward after cutting for silage is also linked with dock establishment. Poor grass management leading to overgrazing and poaching allows dock seedlings to emerge and grow. Fewer broad-leaved docks are found on grassland grazed by sheep or subject to flooding but it may be frequent on trodden ground in pastures and in gateways. Broad-leaved dock is also found in arable crops, field margins and waste places.

Broad-leaved dock is able to grow on a range of soils except the most acid. Soils high in nitrogen or low in potassium are said to favour docks. However, some research has shown a clear link between increasing dock populations and increasing levels of soil potassium. But other studies concluded that increasing the potassium status did not favour docks.

There are some who would argue that docks in grassland are not weeds because they contribute to the herbage and hence do not need to be controlled. They may also contribute trace elements to a grazing animals diet. Broad-leaved dock is relatively high in phosphate and potassium levels in the leaves, and is particularly high in magnesium. Cattle fed on the herbage containing docks are said not to suffer bloat because tannins in the dock leaves precipitate out soluble protein in the rumen liquor.

In the UK, broad-leaved dock is a host for the potato eelworm, Ditylenchus destructor. Docks also serve as alternate hosts for the bean aphis and mangold fly, and encourage subterranean larvae such as those of the swift moth.


Biology: Broad-leaved dock flowers from June to October but flowering is delayed by early shoot removal. A large mature broad-leaved dock can produce up to 60,000 ripe seeds per year. The seeds become viable from the milk stage onwards and immature seeds will continue to develop on stems cut down just a few days after flowering. Broad-leaved dock can shed seed from late summer through to winter but the seeds may require a short after-ripening period before being ready to germinate. Seedlings of broad-leaved dock generally do not flower in the first year.

There is considerable variation in germination characteristics between seeds from different populations, different plants, different panicles on the same plant and seed from different positions on the same panicle. Some of this is due to seed size and seedcoat thickness, some to the time of ripening and some is due to maternal factors. Defoliation can also affect seed development and germination characteristics. Light, alternating temperatures, chilling, nitrate and seed scarification can all help to promote germination.

The seeds germinate any time that conditions are favourable but the main flushes of emergence are in March-April and July-October. Seeds germinate best on the soil surface or in the upper 10 mm layer of soil. However, in the summer when the soil is warmer seedlings appear to emerge from deeper in the soil. In a clay loam soil, seedlings emerged from between 0 and 70 mm deep. Germination is inhibited under a dense leaf canopy. Seedlings have a low competitive ability but once the deep taproot has developed the dock plant has an advantage over shallow rooted crops and grass. It then becomes more difficult to eradicate.

Established plants can withstand trampling and mowing. New shoots are quickly sent up after decapitation and repeated regeneration may lead to the development of large clumps. The underground parts of a dock consist of a vertical stem and a branched taproot with a transition zone between them. The underground stem may reach 5 cm in length and is kept below ground by root contraction. Broad-leaved dock overwinters as a rosette with small dark-leaves and stout taproot. In spring, new leaves develop rapidly and there is a vegetative phase of elongation.


Broad-leaved dockPersistence and Spread: Dock seed numbers in soil have been estimated at 5 million per acre. The seeds contain a chemical that inhibits microbial decay and are capable of surviving in undisturbed soil for over 50 years.

In pasture, individual plants of broad-leaved dock can be very long lived, forming compound crowns with multiple taproots. There is considerable confusion about the ability of docks to regenerate from these underground organs. Some authors maintain that true roots do not regenerate and only the stem and transition zone can regenerate. Others insist that all parts will form new shoots if detached from the parent. At present it is


Management: In resown grass/clover infested with dock seedlings, cutting will reduce seedling numbers initially. Increasing the cutting frequency will reduced root biomass but may not improve seedling losses. Mowing has little effect on established docks but will prevent seed production. Frequent cutting aids seedling development and encourages regeneration of taproots and branching of the shoots of established plants, increasing the potential for future growth. It was reported that when the sward was cut frequently (5-7 cuts per year) the presence of docks had little effect on yield. When the sward was cut less frequently (3-4 cuts per year) total yields were reduced and the herbage contained a high proportion of dock foliage. In a pasture heavily infested with docks the best option may be to plough and reseed with grass but not immediately. The docks are likely to regenerate both vegetatively and from seed, and a period of fallowing or arable cropping may help to reduce re-establishment.

In any grassland it is prudent to avoid sward damage from trampling, poaching and uneven slurry application. Cattle slurry has a high content of potassium well in excess of the optimum needed for good grass growth and docks are able to take advantage of this. It is best to apply slurry early in the year at moderate rates or as a split application.

Docks are grazed off by cattle, sheep, goats and deer but not by horses. It has been suggested that sheep should be used to graze off seedling docks in the autumn and mature docks in March

Further Information / Links:


Take part in our trials on docks (Experiments 1, 2 and 9)
»UK farmers' case studies

» See the results of the monitoring trials

» See the results of the dock pulling trials

» See the results of the dock beetle trials

« Back to Perennial Broad-leaved Weeds

Comments

  1. Just a wild thought! We may spend hours trying to mechanically remove docks, to hand weed them, but....... could we be just as effective if we had a large syringe with large needle and patrolled the fields injecting them with a super-dose of, say, neat saline? Or some other allowable organic input. They have a fat enough target root to be able to inject - I've done it with other weeds invading our lawn, but not using salt!!
    - Oliver Dowding 5---0-2004

  2. The weed spear that we looked at last year is a variation on this theme with a hot spike that goes down into the dock. Unfortunately with some of the older docks it is difficult to find a central tap root to jab into- docks tend to fragment as they get older. We have some drawings of this process which I hope we can show on the open day !
    - Gareth Davies 5---0-2004

  3. Iam noticing verystunted growth and some dead leaves in one grass field. Plants have red dots on leaves that spread killing the leaf. how can I spread this disease to other fields as at present it appears to be the most effective control I have seen.
    - David Leech 5---0-2004

  4. The disease in question is probably Ramularia rubella that is quite common on docks, especially on broadleaved docks. It generally does not kill the docks but will impair plant functioning if enough is present on the leaves. The disease is found everywhere and is spread by air and so you should not have to spread it yourself. However, I have not been able to find any information on the conditions under which it develops best and which might help to encourage it.
    - Gareth Davies 5---0-2004

  5. I have found a large patch of docks that have a lot of damage. The leaves appear purple/red from a distance and look to have shot holes in them, on closer examination they could have had insects chewing off the surface both top and bottom. Have you any ideas?
    - David Redgate 5---0-2004

  6. The red spots are probably due to a disease Ramularia rubella that is quite common on docks, especially on broadleaved docks. It generally does not kill the docks but will impair plant functioning if enough is present on the leaves.

    The holes in the leaves are often caused by the dock beetle Gastrophysa viridula that eats docks. The larvae are generally small black insects found on the leaves whilst the adult beetles are generally a shiny metallic green. Let us know if you see any on the plants. We are working to map out where they occur in England and Wales in order to find out what encourages them.

    - Gareth Davies 5---0-2004

  7. The beetle you have observed is almost certainly the dock beetle Gastrophysa viridula. It occurs on docks from April to October. Currently the adults are emerging from the soil under the plants where they overwinter and laying eggs. The larvae are small black insects that emerge from yellow eggs (normally laid on the underside of the leaves) and can often completely defoliate docks. I will try and get some pictures on the website as quickly as possible.

    We are currently working on many aspects of dock management, one being possible biological control by beetles. I would be grateful if you could fill in our survey form to indicate some details about the beetle on your farm. The hope is that we can build up a picture of conditions that are likely to favour the beetle so that farmers can encourage it as part of their dock management strategies.

    Please click on the link below to see the latest results on the survey and for a downloadable form:

    Dock trial results and survey form.
    - Gareth Davies 5---0-2004

  8. I have been organic for 5 years and have this year noticed insects which are eating their way through docks. In an area of docks 1m2 there are 20 plants and on them 40-50 insects the insect is the size of a small ladybird more oval 6 legs 2 antennae dark green luminous in the light orange/yellow. I have looked on your web site for a picture but cant find one. Could you please send me any info you have many thanks

    - M. A. Stimpson 5---0-2004

  9. Has anyone had any experience of improved dock control in areas of high pH?
    - Becky 5---0-2004

  10. I read in the information above that soils low in potassium favour docks. However, I read in some articles of J. Humpreys that high potassium concentration in the soil favour docks. This link is most obvious in old grasslands. Can you tell me where you get your information which is right and why? Thanks a lot.
    - Lisette 5---0-2004

  11. Often the information we have located on docks is conflicting. Sometimes this can be due to the methods used or some other factor. Haggar R J (1980). Survey on the incidence of docks (Rumex spp.) in grassland in 10 districts in the United Kingdom in 1972. ADAS Quarterly Review 39, 256-70. was our reference that stated that docks were favoured by soils low in potassium. I am not aware of the articles you mention but it may be that something like soil pH which can affect uptake of certain minerals was a factor. Do you have the source reference of the articles you refer to?
    - Bill Bond 5---0-2004

  12. The article I refered to was from J. Humpreys, T. Jansen, N. Culleton, FS. Macnaeidhe and T. Storey, published in Weed Research 1999, 39: 1-13.
    In this article they mentioned that sometimes indeed more abundant populations were associated with lower soil K status, but this could be because there is a difference in soil K status between silage swards and grazed swards (p. 8). I also looked if I could find the article you mentioned, but I think I do not have the complete article. You mentioned futher that pH could be a factor influencing the number of docks but in the same article Humpreys et al. mentioned that soil pH as well as P and Mg concentrations did not explain much of the variation in weed abundance in the experiment they describe. Humpreys also made a nice graph were you can see a clear relation between the number of docks and the soil K concentration as well as the clear difference between silage and pasture grasslands. But I am not sure if I can give you the correct reference. I found it in the summary of papers presented at Agricultural Research forum held at 30 and 31 march 1995. Edited by P. O'Kiely, J.F. Collins and T. Storey.
    - Lisette 5---0-2004

  13. The paper by Humphreys et al. does indeed show a strong correlation between higher dock numbers and increased soil K. The research is in a more limited area and is restricted to predominantly perennial ryegrass swards which may have highlighted a response that was masked in the more general survey of Haggar. It could be a local effect but this seems unlikely. The weed pages have been amended accordingly & the PDF file will be revised in due course.
    - Bill Bond 6---0-2004

  14. We are located in the SP8 post code not far from Shaftesbury and have about 1 acre of natural paddock/veg garden. Currently we are completely inundated with Green Dock Leaf Beetle which is good as far as the control of dock is concerned although they are attacking after seed setting and do not as far as I can see eat the seeds, only the leaves.
    Unfortunately they are quite happy to eat the leaves of rhubarb and grape vine as well which is annoying. Can you recommend a non toxic control to prevent damage to plants which are required for consumption.


    - David Willoughby 6---0-2004

  15. Managing Docks in Hay Meadows

    When we began organic farming 15 years ago we took on, amongst other land, 7 acres of permanent hay meadow. After some four or five years of cutting every year and feeding the hay to our overwintering sheep on the meadows, we suddenly had an explosion of docks across them.

    What we hadn't realised was that dock seeds are not broken down in the sheep's gut, so our flock was doing a grand job of spreading dock seedlings right across the fields.

    We tackled this the hard way. For some five or six years, we walked the meadows while the hay was drying, picking out the dock stalks by hand and bagging them up safely (head down in the bags). At first we burned them, now we take them to the local green-waste tip (we hope their composting process is a good hot one).

    After a few years of this, the population of docks was reduced to much the same as when we began the process. We now pick out the dock stalks when we see them but no longer need to be obsessive about it.

    The sheep graze the aftermath and on through the winter, and seem to keep the foliage under control.

    Incidentally, we find the docks in our orchard are kept very stunted and struggling by the laying hens, who keep the growing leaves well shredded.
    They don't eat the seeds or roots but are a great deterrent.

    We no longer plough our fields so don't have the disaster of chopping up and spreading such things as dock and creeping thistle!
    - Ann Eggleton 7---0-2004

  16. In reply to David- thanks for the observations about dock beetles. We have seen some high infestations this year and yours is the first report of them eating crop plants. If the beetles build up at the right time they can prevent the docks seeding but this does not happen often (at least in the places we have so far observed them). We have seem them feeding on redshank were docks have been erradicated so it seems that they can switch diets to plants in the same family if docks are in short reply. If you have a small area they are easy to dislodge by knocking the plants as they seem to have a natural mechanism that causes them to drop. If repeated enough times the population should be reduced?
    - Gareth Davies 7---0-2004

  17. Thank you for your reply. We seem now to be through the infestation and they have certainly prevented younger docks from setting seed as these plants seem to seed later than the established roots.
    We certainly noticed a tendancy for the beetles to drop when the plant was disturbed but they appeared to be able to recover quite quickly and return within say half an hour. Obviously the answer is to lay fleece under the rhubarb etc and collect the insects when they fall removing them to a healthy distance and preferably below part of our dock crop!!
    Do you have any information on the life cycle of the Dock beetle which might give indications of their periodicity, length of larval life and adult life and the conditions which cause a hatch so that we can prepare for them next year. Are they related to the ladybird genus? Can they fly or do they just drop. We have not seen any sign of flight.

    David Willoughby North Dorset 19-07-2004
    - David Willoughby 7---0-2004

  18. The life cycle of the dock beetle has been quite well described- adults overwinter in the soil (under plants) and emerge in spring to feed on and lay eggs on docks. Adults can live up to 2 months but normally only for a much shorter period (two to three weeks). The eggs hatch after a week or so and the larvae emerge. The larval period (three stages) lasts up to a month after which they pupate and turn into adults to repeat the cycle. In some locations in the UK the beetle is able to go through three such cycles in a season depending on temperature and food availability. There is some evidence that they are quite heavily predated by spiders and other generalist predators. We have suggested that warmer conditions in spring should bring them out earlier (see our trial results pages)
    - Gareth Davies 7---0-2004

  19. I have a problem. Some public ground near to where I live has an infestation of broad leaved dock weed, along with creeping thistle and japenese knotweed. Our local parish council has the idea of weedkilling the entire area. This is unexceptable. The area in question is a recreational area that is used for sports, dog walking amongst other things, it is also a natural habitat for wildlife and wild flowers. I have been given the task to gather information on exterminating these weeds in a more environmentally friendly manner. Can you help with suggestions on what I can do or post further links or other places where I can get information from? I would really appreciate your help.
    - Mike Havelock 0---1-2004

  20. Your local wildlife society may have some experience of dealing with weeds in this sort of situation. Whatever you do will not provide a one-off solution ..even the the Parish Council would need to repeat a weedkiller applications for several years, assuming they can find a safe & effective material to use in a public place. The simplest solution is to strim the weedy patches, if you have more hand labour then dig out the docks and Japanese Knotweed and pull the thistles. But the operation will need to be repeated to deal with any regrowth. The remains of the weeds, particularly the Japanese Knotweed must be disposed properly so they do not start another infestation eslsewhere.
    - Bill Bond 0---1-2004

  21. Green dock beetles happily working in our corner of North Devon. We collected and moved lots a few springs ago from the more sheltered fields where they overwinter in the hedges to the more exposed fields at the top of the farm. If a good population get going on a plant early enough they appear to kill it. Lazy dog forks then can tackle the survivors. Lazy Dog operators not so easy to find!
    - Sue Batstone 2---1-2004

  22. Has any one tried Barrier-H on small areas with dock problems?
    - R Bickford 1---0-2005

  23. What is Barrier-H?
    - Duncan Gaudie 2---0-2005

  24. Barrier H, a herbicide based on citronella oil, has been developed specifically for the control of ragwort. Barrier H is applied as a spray directly onto the plants and destroys ragwort at all stages of growth. The product was licensed in 2000 as a Ministry Approved Pesticide but does not fall under COSHH regulations. I am not aware of its use on docks nor am I sure of how it is regarded by the Soil Association.
    - Bill Bond 2---0-2005

  25. On the Farmers Weekly site there is a discussion "Could Tazer guns be used for weeding?"

    Unfortunately the thread doesn
    - Duncan Gaudie 6---0-2006

  26. Duncan- the use of high voltage to kill weeds has been considered and even tested in several research projects (see our review on thermal weed control ). It seems that the shortcomings of the method (prinicipally the necessity of getting good contact between weeds and electrode) and danger of using the high voltages necessary put an end to the idea.
    - Gareth Davies 6---0-2006

  27. Murray- biodynamic farmers have a method that involves collecting docks, burning them and them preparing a liquid spray with the ash which they then apply to the infested land. You would need to obtain the exact details from a biodynamic farmer. I should add that as part of this project we did look at this but we did not find any direct evidence that such a method worked without also following other tried and tested management methods as well.
    - Gareth Davies 6---0-2006

  28. I have 3.5 hectares of bare land covered in docks, I have heard about a method of killing docks by collecting & burning the docks & redistributing the burnt ash over the land? have you heard of any such practise?
    - murray mullins 6---0-2006

  29. "I have heard about a method of killing docks by collecting & burning the docks & redistributing the burnt ash over the land?" - Oh, for goodness sake!
    - Paul Dear 8---0-2006

  30. We have just drilled 10 ac. white clover and grass. 7 days later i have a carpet of seedling docks . What should i do ? Field had been in spring wheat was ploughed, power harrowed and drilled. I have a beef suckler herd and could have acceess to sheep. Should i cut my losses and spring tyne harrow the seedling docks and reseed with broadcaster in a few weeks or persist with the new ley and try and eradicate docks another way?
    - Richard Arundell 9---0-2006

  31. Richard- I think that the docks are unlikely to be completely erradicated by spring tynes and so any reseeded clover and grass is likely to be behind the surviving docks. Many of the seedlings are likely to die by self thinning but some will survive and once they reach 40 days old are capable of regeneration from the root. It has been suggested that sheep can graze off seedling docks in autumn through to spring and this might allow the ley to establish and come through?
    - Gareth Davies 0---1-2006

  32. I have 10 acres of grazing for 4 horses & I cut my seed heads off regularily and burn them, but the clumps dont seem to reduce any!!! The farmer who I bought my paddock from has free range chickens for eggs and sprays the chicken manure on the fields each year. The farmer who cuts & bales me said that Docks are always present where chickens are!?...... The clumps are too big to dig out with my rag fork. I have just seen a new weedkiller/spray but its very expensive. Its called "Ragtime" and ive been told it does work. So.... do I carry on killing my back & cutting them down manually, or try this spray??? But if I spray them, wont I have to keep doing it??
    - Karen Baker - Wiltshire 7---0-2007

  33. i just want to know what problems dock causes with stock and how we can control it. this web site has just told me what it is not what it does!
    - sarah emralds 3---0-2008

  34. I have recently moved my horse to pasture which is massively infected with docks. My husband and I have dug out well over 500 plants in the last two weeks, only a fraction of what remains. I was alarmed to read that by dumping the excavated plants in our muck heap to rot down I risk infecting other pastures. The plants are still in winter mode, being February but I am taking full advantage of the soft ground, caused by the recent torrential rains, to remove as many as possible.


    - Pat Dexter 3---0-2008

  35. I have a new vineyard in Devon which I'm afraid to say has a lot of docks in it. I've discovered recently that there are green dock leaf beetles on these docks but they are also on the grape vines and seem to be eating the vine leaves. Does anyone know of a natural predator for these beetles which could be introduced to control their numbers? I don't want to use insecticides.
    - Ken Bennett 7---0-2008

  36. Has anyone heard of the dock leaf causing problems to horses feet in the form of scabs?
    - Laurence Fowles 7---0-2008

  37. Seeing as livestock and insects eat dock - Is it an edible weed for humans?
    - Simone Cobb 9---0-2008

  38. We have lived in North Devon for 20 years, and have a field of about 6 acres. I have not seen a dock until this year, and now there are 200+. The tenant farmer changed 2 years ago. The first tenant grazed for 3 months, then fertilized, and finally cut silage in late July. The new tenant also grazes, although with more density, hence it is grazed much lower. He also muck spreads Nov/dec, something the previous farmer never did. Clearly, our problem is either over grazing, or the slurry is contaminated with dock seed. In addition to sheep, he runs a nearby dairy farm. I propose to strim them off completely before they are hidden by grass growth. Am I wasting my time ? Should I find a new tenant !
    - Edward 1---1-2009

  39. Burning needs a fuel source and so two collections, one for docks, the other for fuel. Would drowning for a month or deal with docks as it does with other perennials?
    - A. Hobbs 1---1-2009

  40. Burning needs a fuel source and so two collections, one for docks, the other for fuel. Would drowning for a month or deal with docks as it does with other perennials?
    - A. Hobbs 1---1-2009

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