Blackberry

Scientific name: Rubus fruticosus

Blackberry flowers

Blackberry fruit

Young blackberry plant

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

  • Prickly perennial woody shrub, with long arching branches, often reaching more than 2 m tall
  • Stems have very sharp backward pointing thorns and can reach up to 8 m long, becoming entangled with each other
  • White to pink flowers 2 – 3 cm across, each with five petals and many stamens occur in clusters in summer to late spring
  • Edible blackberries appear in summer to autumn
  • Leaves usually have five to seven oval leaflets, with prickly stalks and mid-ribs
  • Underside of leaf is pale in colour
  • New shoots can arise from the roots
  • Common in waste areas, hedges, roadsides, scrub, and sometimes even in swampy ground.

Origin

  • Originally introduced by early European settlers for hedgerows, soil erosion control and as a food source
  • Now declared a pest plant it invades natural ecosystems, smothering native vegetation. It is also a problem in pasture, plantation forests and other disturbed areas.

Related species

  • Three native blackberry species are present in New Zealand: Rubus australis, Rubus cissoides and Rubus schmidelioides
  • These are found sprawling or climbing in native bush. Stems are long and semi-woody with backward pointing thorns, often obstructing humans or animals as they move through the bush.

Life cycle

  • Seeds germinate in the spring
  • Stems root when they arch over and contact the ground, forming daughter plants
  • Seeds are mainly dispersed by birds feeding on the berries. Other dispersal mechanisms include water (rivers, creeks, and floodwaters), soil movement and animals which graze blackberry fruits
  • When the plant has been grazed or suffered other physical damage it can re-sprout from the roots.

Benefits

  • Provides food and shelter for many birds
  • Provides food and nectar for bees and small insects
  • May help in the regeneration of native species.

Impact on pasture

  • Can invade poorly maintained pasture, reducing the stock-carrying capacity
  • Can be a problem in forest plantations and other disturbed areas.

Impact on stock

  • Sheep can become tangled in the sprawling canes and starve to death
  • Goats will readily graze blackberry, sheep will eat fresh growth, but cattle avoid it.

Grazing management

  • Blackberry can be grazed by sheep and goats, especially in the seedling stage, and this can help suppress its growth. Goats fenced onto areas of blackberry or tethered near it can destroy plants completely.

Manual removal

  • Individual plants or small patches can be dug out. However, ensure root crowns and stems are disposed of properly. If left on the ground they may re-sprout and form ne roots.

Chemical control

  • Herbicides can be used between late summer and autumn
  • When spraying re-growth, make sure stems are at least one metre long with fully expanded leaves; large leaves absorb herbicides more effectively.

ALWAYS READ PRODUCT LABELS BEFORE APPLYING

Active ingredient When to apply Residual effect Grass damage Clover damage
metsulfuron-methyl Nov – June Yes Moderate Severe, long-lasting
triclopyr 600 EC Jan – May Yes No Severe
picloram/ aminopyralid/ triclopyr Jan – May Yes No Severe, long- lasting
glyphosate Dec – April No Severe Severe but not long-lasting

Consult your farm consultant, industry rep or New Zealand Agrichemical Manual for more information about chemical control.

Biological control

Blackberry rust (Phragmidium violaceum)

  • Native to Europe, the rust was first discovered here in 1990 and is thought to have blown over from Australia
  • The rust will infect most plants; some may have immunity to it
  • Causes small (2-3 mm diameter) purple-brown spots on the upper surface of the leaves and yellow or black powdery spots on the underside of leaves
  • There are different strains of the rust but  telling them apart is very difficult
  • Signs of the rust can be seen any time of the year but are most prominent in autumn
  • In the summer the rust produces yellow spores: heavily infected leaves are killed
  • Manually spreading the rust won’t help; plants not affected will probably be immune to it. However, slashing plants can increase their vulnerability to rust.

  • 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.