Caucasian speedwell, creeping speedwell, round-leaved speedwell
Veronica filiformis L.
Slender speedwell was introduced from Turkey in 1808 as a rock garden plant. It was first reported as an escape from cultivation in 1838 and is now established throughout Britain. It has become naturalized in gardens, lawns, grassy paths and banks, and on roadsides. Lawns can become densely infested with slender speedwell covering 80-90% of the grassed area. Once this happens, too little grass remains to re-establish a desirable grass cover. Creeping speedwell spreads more rapidly in the shade but thrives in sunny sites too.
Slender speedwell flowers from April to June. It is self-sterile and rarely if ever sets seed.
Plants overwinter as creeping stems on the soil surface.
It spreads entirely by the stem fragments carried on feet, lawn mowers and in lawn cuttings. The fragments root readily.
Lawn cuttings from infested lawns should be collected during mowing and not used as mulch. Composting should destroy any stem fragments among the grass cuttings.
Updated October 2007.