Once established Selfheal spreads quickly via underground runners known as rhizomes and by seed.
Leaves - The oblong leaves are bourn in pairs and can be slightly hairy. The leaves are dark green and the edge are often slightly scalloped.
Flower - Selfheal has distinct clusters purple flower bourn on square stems. This weed flowers between June and September.
Habitat - Selfheal thrives in all types of soil types and conditions.
Cultural Control - Ideally tackle this weed early by removing individual plants by hand before it has had time to develop into larger clumps.
If large clumps have already formed they can be dug out by hand too. Regular mowing helps prevent seed head formation. Keeping the lawn in a healthy condition will help discourage weeds.
Chemical Control - Selfheal is a difficult weed to eradicate using chemicals as it is resistant to many selective weed killers. If you go down this route there are a few options with selective weed killers.
You could use a weed killer that contains a 2,4-D mixture (mecoprop-p or dicamba). Another option is a weed killer that contains a mixture of clopyralid and fluroxypyr.
Repeat applications may be necessary to effectively control this weed. Always follow the manufactures recommendation when using chemicals.