Woodrush in lawns
Field woodrush can be a weed of lawns on acid soils. Most gardeners will only become aware that it is present in the lawn when the brown, tassle-like flowerheads appear in spring. These, together with the coarse leaves, can be unsightly in a weed-free lawn. Reducing soil acidity is the main way to keep field woodrush in check.
Latin name Luzula campestris
Areas affected Lawns
Timing Brown flowerheads seen in spring; treat in summer
What is field woodrush?
Field woodrush is a British native, commonly found in pastures, lawns, grassy banks and churchyards. It is one of the earliest flowering grass-like plants and although wind pollinated, the flowers are visited by hoverflies. In West Yorkshire the early flowering was said to indicate that it was time to put the cattle out to pasture and gave rise to the common name of Good Friday grass.
Where you are wanting to encourage a flower-rich lawn, field woodrush may be tolerated. Learn more about making the most of lawns as a wildlife habitat and ways to help our bees:
Field wood rush can be a problem in lawns, particularly under the following conditions:
- It is common in acid conditions, especially where thatch (accumulated dead, fibrous material) has built up and increased acidity. Under such conditions grass growth is too weak to prevent this troublesome weed from establishing
- Field woodrush even grows in chalk and limestone areas where the upper layer of soil has become acidic, due to rainfall and acid-reaction fertilisers such as sulphate of ammonia
Field woodrush (Luzula campestris) is a grass-like perennial. Its broad-bladed, dark green leaves, are fringed with long, silky hairs.
In March or April it produces dark brown flower and seed heads. These are particularly noticeable before mowing has begun.
It spreads via short, creeping stolons (above ground stems).
First, consider whether this can be done using non-chemical means such as digging out. Where this method is 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.
The best way to eradicate field woodrush and prevent it coming back is to apply lime.
Apply ground chalk or ground limestone in late autumn or early winter, after mowing has ended, at 60g per sq m (2oz per sq yd). Do not use hydrated lime.
Many nitrogen fertilisers acidify the soil and are best avoided. Sulphate of ammonia is particularly acidifying. Most lawn feeds won't significantly affect pH, but where high nitrogen fertilisers are needed consider chicken manure pellets or nitro-chalk (also sold as Nitratechalk) which should be neutral in effect, rather than sulphate of ammonia.
Field woodrush is resistant to lawn weedkillers, but those containing mecoprop-P (e.g. Doff Lawn Weedkiller, Crowne Green Lawn Weedkiller or Westland Resolva Lawn Weedkiller Extra) may check growth if repeated applications are made and the soil pH is raised by liming.
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.
Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 1b)