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New Zealand weeds database

New Zealand weeds database , Pātengi Raraunga tarutaru o Aotearoa

Find information on 78 of the more troublesome weeds found in New Zealand agriculture and horticulture.

A – C
D – H
I – P
R – S
T – Z
Contact Dr Harrington

This site is dedicated to informing people about weeds in New Zealand. It has been designed both for members of the public and for students looking for information on weeds.

This database provides information on 78 of the more troublesome weeds found in New Zealand agriculture and horticulture. With over 2000 weeds in New Zealand, we do not cover all species, but you will find many of the weeds that commonly cause problems in our pastures, crops, lawns and gardens.

Each page has information on how to identify the featured weed (with photos) as well as information about the weed and some suggestions on how best to control it.

Understanding herbicides short course

Learn how to control weeds with Massey’s short course Understanding Herbicides. This involves 50 hours of online study. For more information, please contact Dr Kerry Harrington.

A – C

Annual poa

Annual poa is a small grass with light yellowish-green leaves.

Black nightshade

Black nightshade grows berries when mature and has a purplish tinge on its stem and foliage.

Blackberry

Blackberry has hooks on its stem and grows red to black berries.

Bracken

Bracken is the most invasive fern species in New Zealand.

Broad-leaved dock

Broad-leaved dock is a common New Zealand weed with wide leaves.

Broad-leaved fleabane

Broad-leaved fleabane starts as a rosette and then grows tall upright flower stems.

Broad-leaved plantain

Broad-leaved plantain is a common perennial weed found in lawns and pastures.

Broom

Broom is a scrub weed that produces yellow flowers and seed pods similar to gorse.

Californian thistle

Californian thistle is a common perennial thistle with an underground creeping root system.

Cape weed

Cape weed grows as a large rosette with yellow flowers.

Catsear

Catsear is a perennial weed that grows as a rosette with an upright flower stem.

Chickweed

Chickweed scrambles along the ground, has little white flowers, and a single line of hairs on the stem.

Cleavers

Cleavers have foliage and fruits with tiny hooks that can cling to surfaces.

Clustered dock

Clustered dock is a perennial weed with a large tap root system.

Couch

Couch is a rhizomatous grass that can cause problems in flower gardens and crops.

Creeping buttercup

Creeping buttercup has three leaflets and produces shiny yellow flowers.

Creeping oxalis

Creeping oxalis has three leaflets on each leaf and forms dense mats in lawns.

Creeping speedwell

Creeping speedwell grows as dense mats in lawns and has lilac flowers.

D – H

Daisy

Daisy grows as a rosette with white flowers and spoon-shaped leaves.

Dandelion

Dandelion grows as a rosette with upright flower stems topped with a yellow flower.

Fathen

Fathen is a tall, upright and leafy weed that germinates only in spring or early summer.

Fiddle dock

Fiddle dock grows as a rosette and has leaves shaped like a fiddle.

Field speedwell

Field speedwell has hairy leaves and grows small blue flowers.

Galinsoga

Galinsoga is an upright annual weed that grows flowers with only five small white ray florets.

Giant buttercup

Giant buttercup grows in clumps and produces shiny yellow flowers.

Gorse

Gorse is a scrub weed with sharp spine leaves and yellow flowers.

Great bindweed

Great bindweed is a vine that produces heart-shaped leaves and large white flowers.

Groundsel

Groundsel grows throughout the year, producing wind-blown seeds.

Hairy buttercup

Hairy buttercup produces shiny yellow flowers and has sepals below the flower petals that point downwards.

Hawkbit

Hawkbit grows as a rosette with yellow flowers on wiry, unbranched stems.

Hawksbeard

Hawksbeard starts as a flat rosette then produces branched leafy stems with yellow flowers.

Hedge mustard

Hedge mustard has small yellow flowers and can grow more than one metre in height.

Hemlock

Hemlock is a poisonous weed that can grow over a metre in height with large white flower heads.

Hydrocotyle

The hydrocotyle genus has 15 species with similar biology and control that are difficult to differentiate.

I – P

Ivy

Ivy is a vine-like weed very commonly found in gardens.

Mallow

Mallow genus has four common species in New Zealand.

Manuka

Manuka is a native New Zealand scrub species with large numbers of small leaves.

Mouse-ear hawkweed

Mouse-ear hawkweed has long hairs on its foliage and flower stems.

Musky storksbill

Musky storksbill starts life as a rosette, with each leaf made up of a series of leaflets.

Narrow-leaved plantain

Narrow-leaved plantain is a common perennial flat weed.

Nettle

Nettle has jagged leaves with hairs that inflict a sting on your skin if you touch it.

Nodding thistle

Nodding thistle is a competitive thistle with a large seed head that tips over.

Old man’s beard

Old man’s beard is a vine-like weed commonly found in waste areas and bush reserves.

Onehunga weed

Onehunga weed is a small turf weed with finely divided leaves that produces prickles.

Oxeye daisy

Oxeye daisy grows as a rosette and then produces long leafy flower stems.

Parsley dropwort

Parsley dropwort is an invasive pasture weed with tubers on its roots.

Parsley piert

Parsley piert is a small weed that grows commonly throughout New Zealand.

Paspalum

Paspalum is a grass weed with short stout rhizomes, joining weeds together to form dense clumps.

Pennyroyal

Pennyroyal has creeping stems and leaves that, when crushed, smell like mint.

Pink shamrock

Pink shamrock re-establishes from bulbs in spring and has very pale pink flowers.

R – S

Ragwort

Ragwort starts as a rosette, and when mature produces an upright stem with yellow flowers.

Red dead-nettle

Red dead-nettle has jagged leaves and produces lilac flowers.

Redroot

Redroot is a tall, upright weed that can grow over a metre in height.

Scarlet pimpernel

Scarlet pimpernel grows along the ground and produces small orange flowers.

Scotch thistle

Scotch thistle is the most common thistle species in New Zealand with spines on both the leaf surface and margins.

Scrambling fumitory

Scrambling fumitory is a clambering annual weed that produces clusters of pink flowers.

Scrambling speedwell

Scrambling speedwell is a small annual weed that grows along the ground and produces blue flowers.

Selfheal

Selfheal has creeping stems and dark blue flowers.

Sheep's sorrel

Sheep's sorrel has arrow-shaped leaves and reddish upright flower stems.

Shepherd's purse

Shepherd's purse starts as a rosette and then grows an upright flower stem with heart-shaped seed pods.

Sow thistle

Sow thistle is an annual weed with a succulent stem when in flower.

Spurrey

Spurrey has sprawling stems with narrow leaves that grow in clusters along the stem.

Staggerweed

Staggerweed is a small annual weed with lilac flowers and hairs on its square stem.

Stinking mayweed

Stinking mayweed grows annually and has a very strong smell when crushed.

Suckling clover

Suckling clover is a winter annual and is smaller than other clover species.

Sweet brier

Sweet brier is a rose species with small pink flowers and spines down its stem.

T – Z

Tauhinu

Tauhinu is a perennial scrub weed with small rounded leaves.

Tradescantia

Tradescantia is a succulent, brittle weed that can easily break and fragment.

Turf speedwell

Turf speedwell is a small perennial weed that grows along the ground and produces white flowers.

Twin cress

Twin cress is a small weed, starting as a rosette and when mature sends out prostrate stems.

Water pepper

Water pepper has pale pink flowers, long leaves and fruits at the end of the stem.

White clover

White clover has a stolon system and its white flowers have clusters of many florets.

Wild radish

Wild radish has large seed pods and purple veins on pale yellow petals.

Wild turnip

Wild turnip is a tall, annual, competitive weed with bristly leaves and yellow flowers.

Willow weed

Willow weed has leaves similar to a willow tree and grows clusters of small pink flowers.

Winged thistle

Winged thistle establishes each autumn and has spines down the flower stem in spring.

Wireweed

Wireweed is a summer annual that is variable under different growing conditions.

Yarrow

Yarrow is a commonly found weed within pastures and has a deep rhizome system.

Adjunct Associate Professor Kerry Harrington

PhD, MAgrSc(Hons), BAgrSc(Hons)

Associate Professor in Weed Science

K.Harrington@massey.ac.nz

Phone: +64 27 664 1162
Department: School of Agriculture and Environment
College: College of Sciences
Campus: Manawatū

Until his semi-retirement in late 2023, Kerry was the weed science specialist at Massey University. As well as teaching aspects of weed biology, identification and control, he supervised postgraduate students and undertook his own research. Kerry still runs the Understanding Herbicides short course each year for Massey University and deals with questions about New Zealand weeds.