Posted: 21/09/2013 at 09:52
I have found woodrush in the RHS web site
The best way to eradicate field woodrush and prevent it coming back it 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 amonnia.
Field woodrush is resistant to lawn weedkillers, but those containing mecoprop-P (e.g. Doff Lawn Spot Weeder, Westland Resolva Lawn Weedkiller or Bayer Lawn Weedkiller 2) may check growth if repeated applications are made and the soil pH is raised by liming.