A Question of Controlling Rushes

By Anthony O'Connor, Teagasc Adviser, Galway/Clare Regional Unit

The rush is ON!  These days, I'm constantly rushing to answer phone queries on controlling rushes, so, some frequently asked questions answered! 

Q. Why have Rushes become a problem on many farms in recent years?

A. The global warming/wetting weather of recent years and the resultant poaching has left many swards open to invasion by Rushes. Although associated with wet soils and poached areas, clumps of rushes are now a common sight in pasture fields in drier areas.

Q. How come Rushes are so hard to control?

A. Soft Rush, the most common type of rush, is characterised by an erect mode of growth with no leaves and a very tough outer skin, making it difficult to control with herbicides. Also, the plant is deep rooted with large root reserves of food.

Q. What's the best way of limiting Rushes in grassland?

A. Seeds from rushes only germinate if conditions are favourable, maintaining a fertile, dense, leafy grass sward is the best method to prevent Rushes establishing and spreading. Encouraging grass growth will, in turn, reduce the existence of rushes. Having a fertile soil with adequate levels of Nitrogen, Phosphorous and Potassium along with a suitable pH for grass growth is critical. Avoid any poaching, overgrazing or damage to grass swards.

Q. What other grassland management practices will limit Rushes infestation?

A. Frequent topping, timely fertilisation, application of lime along with good drainage will all help limit Rushes spread. 

Q. What's the best method of chemical control?

A. Whether you are licking or spraying, topping 3 weeks in advance of spraying is advised to promote fresh green re-growth capable of taking in the herbicide. This also helps weaken the food reserves within the plant. Remove any mown Rushes before spraying. Soft rush can be controlled with MCPA or 2, 4-D applied in June or July when growth conditions are good. A wetting agent can improve the spray sticking to the slender rush 'target'. These sprays will stunt grass growth and damage/kill White Clover. 

Q. I'm in the GLAS Scheme, with some fields/parcels as Low Input Permanent Pasture - there is a lot of Rushes coming up, what's the best control method?

A. Spraying of Rushes is not permitted on land parcels on farms participating in the GLAS Scheme who have chosen to undertake the Low Input Permanent Pasture or the Traditional Hay Meadow option in this Scheme. Boom spraying with herbicides will damage the grassland plant species present in the sward. This could result in a penalty under Cross Compliance. Spraying is not permitted in any SAC areas. Rushes can be controlled by topping after the 15 July. Consult your GLAS Planner if considering any control of Rushes in land parcels involved in the GLAS scheme. Spot treatment is permitted in these GLAS areas.

Q. There has been a lot of poor publicity about MCPA recently, with the Environmental Protection Agency threatening to take it off the market, why is this?

A. In recent months, high levels of MCPA have been found in some drinking water sources (drinking water sources can be groundwater or surface water). MCPA is very soluble so it can travel easily in waterlogged areas or water bodies. MCPA levels are based on EU monitoring levels. Water will always find water. When using this herbicide, follow manufacturer's instructions and recommended rates carefully. Suggested tips if applying MCPA include:

1. Don't apply if the soil is water logged
2. Don't apply unless the grass and rushes are dry
3. Don't apply if rain is forecast
4. Avoid windy days where spray drift could spread into watercourses
5. Keep back an adequate buffer zone distance from watercourses and water bodies 

Q. What are buffer zones and how do they apply to MCPA?

A. When spraying Ruses with a boom sprayer you cannot spray within 5m of any water bodies or dry drains.

Q. Are there general precautions for using herbicides to control Rushes?

A. Read the product label carefully and follow recommended rates. Spray in the cool of evening or early morning to avoid scorching of grass. Avoid grazing sprayed areas for 10 days post spraying. Triple rinse the empty container and put the washings into the sprayer and spray this onto grassland.