Several
species of speedwell can be a problem in lawns, the most common
being the lesser speedwell, Veronica filiformis.
The weed forms dense mats by producing numerous sideshoots
that root at their nodes.
Speedwells are resistant to the majority of lawn weedkillers available to amateur gardeners. However, products containing the active ingredient fluroxypyr (Verdone Extra or Verdone Extra Ready to Use) will provide some control in lawns.
Weak grass encourages the spread of the weed, so attention should be paid to feeding in the growing season; use a specially formulated lawn food in spring and top up with liquid feeding in the summer. Though the lawn should be mown regularly, do not cut it too close as slightly longer grass will help smother the weed.
Speedwell can reproduce from stem sections scattered by the mower and mowings put on the compost heap may spread the weed to other lawns when used as top dressings if incompletely decomposed. In autumn, scarify, aerate and topdress as necessary.