Pirri-pirri-bur

Latin Name

  • Acaena novae-zelandiae

What’s the problem?

  • Pirri-pirri-bur is non-native species with scattered distribution across the UK with local concentrations in places like Lindisfarne, Northumberland.
  • The plant spreads by ball like hooked seeds which attach to animals fur and peoples clothing, potentially transporting seed over long distances.
  • Once established it can form dense colonies displacing native species.

Legal Implications?

  • Pirri-pirri-bur is not currently listed as a Schedule 9 species under the Wildlife and Countryside Act 1981.

Images supplied by GBNNSS

In Detail

  • The plant is native to South-East Australia and New Zealand. It was originally bought to the UK as an ornamental plant in the early 1900’s and potentially via seeds in imported contaminated wool.
  • Spread of the plant is through seed, dumping of garden material, and vegetatively via fragments of plant.
  • The seed ‘burs’ can be transported long distances attached to animal furs and clothing.
  • The plant prefers open dry ground but will grow in numerous habitats including sand dunes, heaths, cliffs and rough pastures where it forms dense mats of growth.

Identification

  • A mat forming, creeping perennial dwarf shrub which grows up to 11cm in height. Trailing stems can reach up to 1m. The leaves are bright green, growing 3-10 cm long. Leaves are deeply toothed with 5 to 6 leaflets on each side of the leaf, leaflets have a slightly wrinkled appearance.
  • Pale green stems up to 11cm hold the flowers head. The densely packed flower head is spherical in shape and light green/ white in colour. Individual flowers are petal less.
  • Once developed the seed heads, which contain many individual seeds, maintains its spherical shape. Seeds have reddish spines which are barbed at the tips.
  • Seed heads remain visible over winter and can be used to identify the plant.

Control Methods

Mechanical:

  • The plants can be hand pulled, mechanically excavated and removed, although care should be taken to remove all of the plant material as broken stolen has the potential to propagate new colonies.
  • Care should be taken to inspect clothing and animals to prevent the spread of the burs from areas where the plant is known to be present

Chemical:

  • Herbicide application can be effective at controlling populations however in environmentally sensitive areas this may not be the preferred option.  
  • Applications of herbicide are best made after the plant before it has flowered.

When treating large areas, a suitable grass and forb mix should be sown to prevent bare ground and colonisation of other unwanted species.

If you have concerns over Pirri-pirri-bur species on your land, if you are unsure of your legal responsibilities, or, if you would like a quotation for control, please contact one of our specialist surveyors. Treatment costs start at £380.00 + VAT.