What is it?Originally from Brazil, the exotic sounding alligator weed is a dangerous invader sneaking into wetlands, rivers and even subdivisions around the North Island. It's a hollow-stemmed "super weed" with small clover-like flowers and lush, oval leaves. Luckily it doesn't spread by seed in New Zealand, but every small fragment can form a new plant.
Why is it wicked?This alligator devours wetlands, lakes, streams, ponds and drains. It was accidentally introduced near Dargaville in ship's ballast in the 1890s. Since then it has become a major weed of agriculture and the environment around Northland, Auckland, Bay of Plenty and Waikato and has even invaded some subdivisions around Hamilton, living out of water. Alligator weed can spread only via broken stem sections, but unfortunately the stems break easily and are moved about by water, contaminated diggers and farm machinery, fishing nets, boats and trailers. As well as displacing native aquatic and marginal plants, stagnating water and killing fish, alligator weed is toxic to mammals, impedes drainage and contributes to flooding.
What can you do?Learn to recognise Alligator weed and make sure any machinery or recreational gear has been thoroughly cleared before leaving an alligator infested site. Alligator weed is very hard to control so prevention is the best cure. It is illegal to sell, distribute or propagate alligator weed. Contact your Regional Council or local DOC office for advice if you think you have found this plant. For more information, check out www.weedbusters.org.nz
If you want to grow plants in wet areas consider planting flax, native sedges (e.g. Carex) or rushes (e.g. Juncus).
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