0 Weed of the Week: Broadleaf dock (Rumex obtusifolius)

Weed of the Week: Broadleaf dock (Rumex obtusifolius)

By Laurence Gale MSc

What is a weed? By definition a weed is a plant that is growing in the wrong place. Weeds take valuable space, water, sunlight and nutrients that may otherwise be accessible to important crops, in our case turf grasses. Weeds not only compete for these resources they can disfigure and cause problems to playing surfaces.

Weeds are very good competitors and take advantage of any opportunities to colonise turf situations, particularly when the sward is under stress and weak, leaving bare soil areas for weeds to populate. Weeds have many mechanisms and characteristics that enable them to do this, having thick waxy cuticle leaves that can be resistant to some chemicals, fast reproduction methods, the ability to reseed in 6 week cycles and deep tap roots enabling the weed to survive in compacted dry ground conditions.

Weeds have one of three life cycles: annual; biennial or perennial.

  • Annual weeds: Live for a single season. These weeds germinate from seed in the spring or summer, flower and then die.

  • Biennial weeds: Live for two seasons. During the first growing season, these weeds remain in a vegetative stage and, in the following year, produce flowers, set seed and die.

  • Perennial weeds: Live for multiple seasons and flower more than once. Perennial structures (rhizomes, stolons, crowns, entire plants or roots) survive from year to year.

Some weeds may be harmful to the environment or noxious to your regional ecology. For example Japanese Knotweed (Fallopia Japonica) is fast becoming a major weed problem on road side verges and urban landscape areas, a very difficult weed to eradicate. It is very important to recognise weeds and seek effective controls methods to eradicate them from our facilities.

Weeds can also be used as an indicator of soil conditions. For example, knotweed and plantains both indicate soil compaction because they can maintain adequate root respiration at lower oxygen diffusion levels than other plants. Different weeds tolerate different soil conditions, some are alkaline loving and others acid loving. Getting to understand and recognise the physiology of these plants will help you become better turfgrass managers.

This week's weed is: Broadleaf dock (Rumex obtusifolius)

The broad dock is one of our most common weeds, and can be seen in various locations, road side verges, waste ground, ditches and the perimeters of fields. It is easily recognised by it's broad oval leaves which are larger than those of any other native dock.

Scientific name

Family

Life cycle

Rumex obtusifolius

Polygonaceae

Perennial

Form / Appearance

Docks are hardy perennials, able to grow and establish on most soil types. The plant forms muti-stems that bear the leaves. Plants can grow to a height of 1000-1500mm.

Roots

The plant has deep tap roots that are able to penetrate most soils, enabling the plant to establish and thrive in many different environments.

Flowers

Flowers are white/green in colour and change to brown after pollination and once the seed heads begin to dry out ready for dispersal.

Leaves

Dock leaves are large, broad and have a wavy margin. Each leaf has a long petiole, often with a red to pink midrib.

Reproductive method

The plants reproduce themselves from seed. Seed heads form between June and September. Seeds of docks remain viable in the soil for several years.

Habitat

Common in waste ground, rough grassland and as a garden weed.

Miscellaneous info

The roots of docks have been used in traditional fabric dyeing. Yellow is the most typical colour produced by dock. Dock plants are heavy pollen producers which can affect hay fever sufferers.

Cultural Control

Cultural control is restricted to removing the whole plant by hand, the deep roots also make it difficult to remove. The most efficient way is to use selective weed chemicals that can be applied to the plant.

Chemical Control

Treatment by chemicals will be determined by the environment the weed is growing in. Selective weed killers and total weed chemicals can be used ensuring the right type of control is used for the given situation.

Docks growing on sports pitches and in road verges - in and amongst grass species a selective weed killer will need to be used. A total weed killer on docks can be used as a spot treatment.

There are a number of products available for controlling broad leaf weeds.

These chemicals are best used when the weeds are actively growing, usually between April-October.

NON Selective :

  • Tumbleweed pro (Contains 480g/L glyphosate. Scotts.

  • Roundup pro biactive. (Contains 360g/L glyphosate. Scotts.

  • Roundup Pro Green. (contains 450g/l glyphosate present as 590g/l (50.9% w/w) of the isopropylamine salt of glyphosate. Rigby Taylor.

  • Timbrel (Contains 667g/L(44.3%w/w) triclopyr butoxy ethyl ester. (480 g/L triclopyr acid equivalent). Bayer Environmental Science.

Selective :

  • Tritox (Contains 178g/L (16.2%w/w) MCPA 54.g/L(4.9%w/w) mecoprop-p and 15g/L (1.4%w/w) dicamba and potassium salts. Scotts.

  • Intrepid 2. (Contains 20.8g/L dicamba,166g/L dichlorprop-p ans 166.5g/L MCPA). Scotts.

  • Greenor. (Contains: 40g/L fluroxypyr, 20g/L clopyralid and 200g/L MCPA). Rigby Taylor.

  • Bastion T. (Contains: 72g/L fluroxypyr and 300g/L mecoprop-p ). Rigby Taylor.

  • Dormone (Contains 465g/L2,4-D(38.1%w/w) as the diethanolamine salt). A herbicide which can be used near water. Bayer Environmental Science.

  • Supertox 30 (Contains 95g/L (8.8%w/w) mecoprop-p and 93.5g/L(8.7%w/w) as the diethanolamine salts). Bayer Environmental Science.

These herbicides are usually applied as a liquid using watering cans, knapsack sprayers and vehicle mounted sprayers.

Ensure you follow manufacturer's directions, health & safety and product data sheets, and comply with COSHH regulations, when using these chemicals.

Herbicides are an effective tool where high quality turf is desired. However, they must be applied with care and accuracy and in the context of a good overall turf management program. Before using any herbicide, carefully review the label for conditions of use including rates, methods of application, and precautions. Never use a herbicide in any manner contrary to its label and be sure that the herbicide will not injure the turfgrass species.

Visit the Pitchcare Store for Glyphosate Weed Killer and an entire range of contact, systemic & total Weed Killers.

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