Slender SpeedwellAsteraceaeVeronica filiformis
Other names: Round-leaved Speedwell, Threadstalk Speedwell
Family: Scrophulariaceae (Figwort)
Perennial, spreading mainly by creeping stems; the flowers are sterile, so it does not self-seed. A problem in lawns where it is spread by mowing, as small fragments of stem can root. It is a garden escapee, introduced from the Caucasus in the 1830's. In Ireland it was sewn into the clothes of travellers for good luck, to 'speed' them on their journey.
Flowers from April to June - silvery-blue and pale lilac.
Hoe or hand pull. Difficult if widespread in the lawn, rake before mowing to lift the stems, but collect the cuttings to prevent regrowth of the fragments. Scarify and feed the grass, then allow it to grow longer to outcompete the Speedwell.
Weedkillers to use:-
Paraquat, Diquat, kills on contact.
Selective weedkiller containing Dicamba or Mecoprop, treat in March or April, add a little detergent to solution to aid wetting.