Illustrated Guide to
of New Zealand
Weeds of New Zealand
by Ian Popay, Paul Champion & Trevor James
ISBN 0 473 09760 5
by kind permission of the
Zealand Plant Protection Society
Publication or other use of images or descriptive
text on these pages is unauthorised unless written permission is
obtained from the authors and publisher.
of the publication Common Weeds of New Zealand must always
Available from Touchwood
free-floating or lightly anchored, rootless, delicate aquatic perennial.
Has forked, finely divided leaves. Forms very dense under-water
masses of vegetation in freshwater up to 10 m deep.
- Flowers Green
(female), whitish (male), no petals, minute. Solitary in leaf
axils, stalkless, with ten to twenty stamens, adapted for underwater
- Fruit Black
oval nuts 5 mm long, with one terminal and two basal spines.
- Leaves Dark
green, up to 4 cm long, in whorls of seven to twelve densely crowded
at the stem apex and increasingly spaced down stems. Leaves equally
forked once or twice into rather stiff, tapering segments.
- Stems Floating,
submerged, up to 1.5 m long, branched, stiff and rather brittle.
Readily broken by waves, current or boats to float away and establish
in shallow water.
No roots, lightly anchored in sediment by buried leaves and stems.
Still or slow-flowing
freshwater of lakes, lagoons, ponds, rivers and drains.
Locally abundant in
the Waikato River system including hydro lakes. Common in Auckland,
Waikato, Rotorua Lakes, Taupo, Hawkes Bay and Wellington in NI.
Found throughout the world.
May be confused with
parrot's feather (Myriophyllum aquaticum) which has pinnate,
rather than forked leaves. Listed on the National
Pest Plant Accord (see Introduction for details).
of botanical name
= horned leaved, the leaves resembling antlers; demersum (Lat.)
On this site
Reproduced from Common Weeds
of New Zealand:
- Weedbusters is a weeds awareness and education programme that aims to
protect New Zealand's environment from the increasing weed problem.
- A free tool to assist farmers and agricultural professionals in decision-making regarding weed and pest identification, biology, impact and management.
- New Zealand Weeds Key
- An interactive identification key to the weeds of New Zealand. Developed at Landcare Research.
Zealand Plant Conservation Network naturalised plants
- Search for information on more than 2500 naturalise and weedy plants.
Zealand Plant Protection Society
- Their main objective: "To pool and exchange information on the biology
of weeds, invertebrate and vertebrate pests, pathogens and beneficial organisms
and methods for modifying their effects."
University Weeds Database
- A site providing information about New Zealand weeds and weed control.
It has a series of pages showing pictures of New Zealand weeds, notes on
identification and control. It also provides information on a university
paper entitled Controlling Weeds.
- Weeds in Australia
- Weeds website of the Australian Government.
Society of Victoria
- Promoting wider awareness and interest in weeds and their management.
Includes a useful page of links
to other weed societies.
Valley Weeds Strategy
- Listing of common and botanical names, images, and information including
control methods for weeds found in Tasmania, and also weeds of national significance.
and Exotic Species of North America
- Images and other information from the University of Georgia.
- Weed-related resources including weed science, practical tools, gardening
tips about controlling weeds, and environmental news updates.
Species Specialist Group
- "The ISSG aims to reduce threats to natural ecosystems and the native
species they contain by increasing awareness of invasive alien species,
and of ways to prevent, control or eradicate them."
- Site that includes a comprehensive collection of weed images from around
on Weeds from FetchBook.Info