Naturalised Plants

Many introduced plants have adapted well to the New Zealand environment. Over 30,000 introduced plant species occur in New Zealand, arriving here either deliberately or accidentally. Of these introduced plants, over 2,500 have naturalised into the New Zealand environment meaning they have established and are reproducing in the wild. Of these naturalised plants more than 300 plants have become environmental weeds meaning they impact detrimentally on the structure, functions or composition of New Zealand's indigenous plant communities, waterways and fauna.

Kikuyu grass (Pennisetum clandestinum) is 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.

Evergreen buckthorn (Rhamnus alaternus), from the Mediterranean, is an example of a shrub that is spreading rapidly in lowland and coastal areas in New Zealand . The species is dispersed by birds, tolerant of shade and drought, and forms dense colonies that can dominate sites and out compete native plants - altering the plant community structure where it invades.

Marram (Ammophila arenaria), an exotic sand binder from Europe, was also deliberately planted around New Zealand in coastal areas as a ‘dune stabiliser' and stock food. It builds high fore dunes that swamp the smaller dunes produced by our native sand binders, spinifex and pingao, and buries threatened native turf field and dune slack communities.

Here we provide information about all of New Zealand's naturalised exotic plant species (including those that have become environmental weeds). We also provide an on-line form for you to record your observations of occurrences of naturalised plants:

• To download a list of naturalised plant in New Zealand - click here
• To search for a naturalised plant - click here
• To browse for a naturalised plant - click here
• To record an occurrence of a naturalised plant - click here

For more information about how to join Weedbusters (the national weeds awareness and education programme) and get involved locally with helping stop the spread of weeds go to www.weedbusters.org.nz