First, consider whether this can be done using non-chemical means such as digging out or suppressing with mulch. Where these methods are not feasible, chemical controls may need to be used.
Consider non-chemical options first. Speedwell is less likely to be a problem in healthy lawns. Boost grass growth to discourage the spread of the weed by feeding with spring and summer lawn feeds. In autumn, scarify, aerate and top-dress as necessary. See our advice on autumn lawn care and spring and summer lawn care for further information.
Though the lawn should be mown regularly, do not cut it too close, as slightly longer grass will help smother the weed.
Ensure that compost containing lawn clippings contaminated with speedwell is thoroughly broken down before use.
Where speedwells occur in borders, hoe regularly, rake off the weeds and then let them dry out thoroughly before adding them to the compost heap. Alternatively, mulch the bare soil to smother the weeds. Destroy any shoots which succeed in growing through the mulch.
Always read weedkiller labels carefully before buying or using, to ensure you choose a product that is best fit for purpose. Take particular care when using residual weedkillers as these persist in the soil for several weeks or months and can move deeper or sideways in the soil, leading to possible damage of underlying plant roots.
Speedwell in established lawns
Speedwells are resistant to the majority of lawn weedkillers available to amateur gardeners. However, products containing the active ingredient fluroxypyr as one of their ingredients (Weedol Lawn Weedkiller or Weedol Lawn Weedkiller Ready to Use) will provide some control in lawns.
Speedwell in new lawns
Weedkillers often cause severe damage if applied to lawns within six months of sowing or turf-laying. Materials containing fluroxypyr as one of their ingredients, however, are claimed to be safe to use after only two months.
Do not add the first lawn clippings after application of a lawn weedkiller to the compost heap. To avoid possible contamination of compost, do not collect the clippings at all but mow frequently and allow the short clippings to remain on the surface of the lawn. These will quickly disperse to leave an acceptable finish.
Speedwell in beds and borders
Spot treat using the non-selective weedkiller glyphosate, taking care to avoid all contact with cultivated plants. Glyphosate is most effective between June and September. Use the gel (Roundup Gel) or ready-to-use spray (e.g Roundup Fast Action Ready-to-Use, SBM Job done General Purpose Weedkiller, Doff Glyphosate Weedkiller Ready-to-Use) on patches of speedwell. Leave the weed for three to four weeks for the weedkiller to take effect, before removing dead foliage.
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 and 4)
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: using spot and broad-scale weedkillers
Weeds: non-chemical control