Selfheal is made up of creeping stems, which allow it to form dense mats within lawns. It has leaves in opposite pairs along these stems. It is often confused with Pennyroyal although Pennyroyal has a mint smell when crushed, which Selfheal doesn’t.
During flowering, it has quite large flower heads at the end of each stem, which are composed of successive layers of dark blue flowers forming on top of each other.
Its tolerance of many selective turf herbicides makes it a problem weed. Selfheal is not an easy weed to control selectively in turf. It appears to regrow successfully following applications of MCPA, 2,4-D, clopyralid or triclopyr when used by themselves. A dicamba/2,4-D mixture is the most common recommendation for this species, applied at flowering in spring while the soil is still moist. It doesn’t always give 100% control, but is better than most other treatments. A triclopyr/picloram mixture (Victory Gold, Triumph Gold, Tordon Gold or Conquest) will also give reasonable control, though this is one of the few broad-leaved turf weeds that will often regrow following treatment with this mixture.
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