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Story: Weeds of agriculture

Alligator weed

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Alligator weed

One of the world’s most serious aquatic weeds, alligator weed (Alternanthera philoxeroides) was accidentally introduced to New Zealand, and was first discovered near Wairoa in 1906. It grows on land and in water, spreading aggressively from even the smallest stem fragments. It can double in area in less than two months.

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Landcare Research – Manaaki Whenua

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How to cite this page

Ian Popay, Weeds of agriculture – Weeds in water and in ecosystems, Te Ara – the Encyclopedia of New Zealand, https://teara.govt.nz/en/photograph/16482/alligator-weed (accessed 4 June 2026).

Story by Ian Popay, published 1 March 2009.