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Invasive Weed Identification

Widely dispersed weeds which have a significant negative impact on native diversity
Moth PlantAraujia sericifera

"Just about pure evil in the plant world. It's unbelievably invasive and very difficult to pull out - it is toxic and causes severe itching. It has 'reasonably attractive' white flowers in February but its choko-like pods contain a mass of thistledown-like seed which can be spread 60km to 70km. It is highly versatile - climbing fences on bare industrial land - and shade-tolerant, capable of crushing forests by climbing canopy trees. Even in really dense forest like in the Waitakeres or Hunuas we have moth plant coming up in the middle."

- Jack Craw - ARC Biosecurity Manager -

Woolly NightshadeSolanum mauritianum

"To the untrained eye woolly nightshade appears to have been carefully planted along the roadside between Hamilton and Auckland. Its other names are tobacco weed, flannel weed or kerosene plant and is in fact a South American weed with potato-like flowersFlowers. As with many introduced pests, it was brought here deliberately in the 1880s. Through parts of Northland it is now among the most common plants on show and specimens of up to 10 metres in height are common. That is due in no small part to the fact that one plant can produce 10,000 berriesBerries in a year. Birds, attracted to its berries, have spread the shrub and its rapid growth leaves native flora in the dark."

- Editorial - Waikato Times -

Climbing AsparagusAsparagus scandens

"Of particular interest is climbing asparagus, which the newsletter describes as 'the single worst weed we have in Laingholm'. It has made inroads into Piha too, and it's hard to get rid of, though not impossible if you keep on it. Climbing asparagus has small delicate fern like leaves and slim but wiry stems. It scrambles over everything,Foliage smothering seedlings and plants, and will grow in shade or sun. Its small white flowers come out round about now, then develop into orange-red berries (September to December). They drop everywhere and birds spread the seeds as well."

- Piha Environment Group -

SmilaxAsparagus asparagoides

"It has a number of features that make it difficult to deal with. Smilax is not just another weed. Its ability to mix in with other plants we don't want to harm prevents anything but the most careful herbicide control. The pale green foliageFoliage of smilax mixes in harmoniously with whatever is around it. Areas of stunted or low growing native plants and regenerating coastal canopies such as pohutukawa and kowhai are particularly at risk. Smilax is increasingly invading coastal areas and both inshore and offshore islands."

- Michael White - ARC Biosecurity Officer -

GorseUlex europaeus

"Perceptions of plants change. Gorse was imported from Britain as early as the 1830s for farm hedging, but it rapidly took over areas of cleared land and farmland and became a serious weed. More recently, research has shown that gorse is a good nursery plant for native bush. If a gorse-covered hill is left for a few decades, native tree saplings will grow up through the gorse canopy. Eventually the gorse will die in the shade of the regenerating bush."

- Bob Brockie - 'Weeds of the Bush', Encyclopedia of New Zealand -

Kikuyu GrassPennisetum clandestinum

"An example of a species deliberately introduced, for use as a pasture and turf grass in northern New Zealand. It is able to form dense mats of stolons and can out-compete and smother lower growing native plants and prevent seedling establishment and regeneration."

- NZ Plant Conservation Network -

Wilding PinePinus radiata

"In areas of native forest regrowth wilding pines are visually intrusive. They compete for space with native plants yet provide none of the advantages these offer, such as berries and nectar for birds and insects. Pine needles form a carpet which discourages regeneration. Ring-barkingRing-barking is an alternative to using herbicides. With a sharp chisel, axe or chainsaw make two deep parallel cuts into the sapwood right around the base of the plant. Vigorous ring-barking is recommended for pines. Cuts should be no less than five centimetres apart and all the bark should be removed from between the cuts."

- DOC Weed Threats -

PampasCortaderia selloana & jubata

"How to tell the difference between pampas and native toe-toe:
1 • Pampas leaves curl at the base of the plant when dead, toe-toe leaves do not. This is probably the single easiest way to identify pampas, it is also what makes pampas a serious fire hazard.
2 • Pampas flowers are erect, toe-toe flowers droop rather elegantly. If it is pink/purple it is definitely pampas but all tend to end up pale grey as they age.
3 • All have leaves that are cutty and sharp - beware! - but the pampas leaves are relatively narrow with a large vein in the centre. Toetoe leaves are smoother, more waxy and the three veins are less obvious."

- Karekare Community Website -

Garden WasteMany ornamental species

"You see it up and down the coastline: weedy ornamental species from urban gardens transplanted into holiday-home gardens, where they are free to seed and spread into neighbouring areas. The problem is garden maintenance, which usually happens only once or twice a year. Some people try to justify disposing of garden waste on sand-dunes, coastal areas and reserves, as stabilising these areas or beautifying them. Others argue that greenwaste rots down with no ill-effects, ignoring the 'weeds' which establish in these areas as a result. Whichever way you look at it, dumping garden waste is just as bad as dumping household waste."

- Weedbusters Newsletter -