Italian arum

Scientific name: Arum italicum
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Low clump-forming perennial (up to 60 cm high), growing from a tuber
  • Leaves are large, arrow-shaped and glossy dark green with distinct white marking along the veins
  • Flowers on a yellow spike are enclosed by a large, pale green, leaf-like sheathing bract
  • Female flowers are on the lower 2 cm of the flower spike, and the male flowers on the upper 8 mm
  • After the leaves die back in summer or autumn, many bright orange berries, each about 1 cm across, form on the flower spike
  • Found in shady spots in older gardens or homestead sites, along hedgerows, in pastures, waste and unkempt places, across scattered damp North Island localities and occasionally in Nelson, Marlborough and Canterbury.

Origin and habitat

  • Native to the Mediterranean, North Africa and Asia Minor
  • Probably introduced to New Zealand as an attractive garden plant. It is still grown in gardens and several cultivars are available from nurseries in New Zealand
  • Found in shady spots in older gardens or homestead sites, along hedgerows, in pastures, waste and unkempt places, across scattered damp North Island localities and occasionally in Nelson, Marlborough and Canterbury
  • First collected in New Zealand in 1945, near Thames
  • Listed as a pest plant in several Regional Pest Plant Management Strategies – consult your Regional Council’s website for details.

Life-cycle

  • Plants spread both by seeds, probably carried by birds, including domestic poultry, and by the tubers
  • Up to 30 small tubers can arise from the main tuber enabling the clumps  to slowly expand in size
  • Although seed viability is high, seedlings cannot tolerate much competition.  Therefore, establishment of plants in closed vegetation is unlikely and in undisturbed grassland any spread is slow
  • The inflorescence generates some heat enabling the volatilization of odours that attract flies to pollinate the flowers.

Benefits

  • The tuber has been cooked and used as a vegetable, and arrowroot can be extracted from the dried tubers.

  • The sap is an irritant and has a burning effect on animal tissues so livestock avoid the plant
  • Its effects on humans are similar so that even though the attractive berries may entice children they are unlikely to eat more than one.

Impact on pasture

  • Not commonly found in good pasture but if present can displace valuable fodder species
  • Usually ignored by livestock but most likely stock will not graze close to the plants.

Impact on livestock

  • Fortunately livestock normally ignore Italian arum so are not likely to suffer from poisoning.

Non-chemical control

  • Even regular cutting or digging out the plants is likely to make eradication a long, slow process.

Chemical control

  • Cutting the tuber and pasting the cut ends with a mixture of metsulfuron-methyl or glyphosate is effective
  • Alternately the leaves can be treated with a weed wiper or spray using metsulfuron-methyl or glyphosate and surfactant
  • ALWAYS READ PRODUCT LABELS BEFORE APPLYING: Consult your farm consultant, industry rep or the New Zealand Agrichemical Manual for more information about chemical control.

  • Popay I, Champion P, James TK 2010. An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.
  • Weedbusters 2014. Arum italicum factsheet (accessed 4 February 2015).