Himalayan wineberry bramble, one of world's worst weeds, discovered in NZ

The Himalayan wineberry bramble, which is one of the world's worst weeds, has been found in Albany.
The Himalayan wineberry bramble, which is one of the world's worst weeds, has been found in Albany.

A weed that is considered one of the 100 worst in the world has been discovered in New Zealand for the first time.

The Himalayan wineberry bramble (Rubus ellipticus) was found growing near Gills Scenic Reserve in Albany on Auckland's North Shore.

The discovery was made by scientists from Unitec's school of environmental and animal sciences last week.

"This is a very significant discovery of a weed that could potentially cause considerable damage to native plant communities in New Zealand if not contained," Unitec's Dr Peter de Lange said.

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"It is difficult to detect at its early stages and equally difficult to remove once the plants are well established because of the density of the thickets it forms."

A Unitec statement said the species was listed by the Plant Biosecurity Index as 'entry prohibited' and its introduction into New Zealand was banned.

"Although not listed as an unwanted organism under the Biosecurity Act, the Ministry for Primary Industries has a watching brief, in particular to make sure that its seeds don't enter the country," it said.

Outside of New Zealand, the Himalayan wineberry bramble was a serious problem in countries like Hawaii, the statement said.

It posed a threat to native communities because of its "thick, impenetrable thickets". 

The weed could easily grow up through forest canopy and smother vegetation.

Its berries, which were edible and tasted like raspberries, were dispersed by birds and meant occurrences of the weed could be random and difficult to detect until plants were well established.

Biosecurity NZ manager of surveillance and incursion Brendan Gould said the detection of the weed was being investigated.

"We have inspected the site to understand the situation and collect samples," he said.

"The samples are undergoing diagnostic testing to confirm if they are the Himalayan wineberry bramble."

Gould said the suspected plants were well established which suggested they had been present for some time, possibly a number of years.

Test results would determine what happens next, he said.

"When unwanted pests or diseases do manage to make it into the country it is almost impossible to work out how they got here."

Because of how well established this weed was, Gould said Biosecurity NZ might never determine how it got here.