• Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • A creeping, mat-forming, leafy perennial up to 30 cm tall with no smell from its crushed leaves
  • The stems lie along the ground and root at the nodes
  • The flowers are tubular, with dark violet petals, arranged in compact cylindrical heads 2-5 cm long at the tops of the stems
  • The flower head has two leaves at its base
  • Plants flower between November and April
  • Leaves are oval, slightly hairy, arranged in opposite pairs
  • Each leaf is up to 6 cm long and 2-3 cm wide. The lower leaves have stalks, the upper leaves are almost stalkless
  • The flowers are occasionally pink or white
  • Usually found in moist or damp lawns and damp, lime-deficient pastures.

Origin

  • Originally native to temperate northern hemisphere regions
  • Introduced to many parts of the world, either because of its medicinal properties or accidentally as a contaminant in grass seed
  • Probably introduced into New Zealand, either deliberately or accidentally, in the early days of European settlement
  • Now common throughout New Zealand.

Life cycle

  • A perennial species which normally remains green throughout the year
  • The flowers appear to be self-fertile.

Benefits

  • Plants have considerable value as herbal remedies for a wide variety of ailments
  • In western medicine it is used externally for treating minor injuries, sores, burns, bruises and can also be used as a mouthwash to treat mouth ulcers

Impact on turf and lawns

  • Selfheal can be very problematic in turf and lawns where it is seen as unsightly and is difficult to remove due to its creeping habit.

Impact on pasture

  • Not readily eaten by livestock and therefore can replace more valuable pasture species
  • Neither is it readily eaten by porina caterpillars so these will tend to encourage the spread of the weed when other pasture species are weakened.

Impact on livestock

  • There are no known adverse impacts on livestock, which are reluctant to eat the plants anyway.

Cultural control

  • Management of selfheal is very similar to that for penny royal, i.e. harrowing to rip up the stolons, improving drainage and possibly an application of lime to raise the soil pH.

Grazing management

  • Appropriate pasture species for the region, suitable fertiliser regimes and good grazing management are the best ways of controlling any weeds in pasture.

Chemical control

  • This species is not easy to control selectively with herbicides in either turf or pasture
  • The usual remedies, MCPA, 2,4-D, clopyralid or triclopyr, are relatively ineffective and some of these can severely damage clovers
  • A safest approach is an application of 2,4-D, applied during flowering in spring. Note however that use of 2,4-D at this time may injure adjacent susceptible crops, especially grapes and kiwifruit
  • A triclopyr/ picloram mixture will also give control, but even this is not a long-term solution. Note, however, that this mixture will also kill all clovers and if used in turf may kill some turf species.

Popay I, Champion P, James T 2010. An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.

Harrington KC, 2017. Selfheal Prunella vulgaris. Massey University weeds database (accessed 15 February 2017.)