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
bottom-rooted, vigorous, aquatic perennial. Occurs in fresh water
and can be up to 5 m tall in still water. One of the oxygen weeds,
denser than Elodea and Lagarosiphon.
- Flowers White,
conspicuously protruding just above surface, up to 20 mm in diameter.
Flowers have three petals 4-12 mm long and nine golden stamens.
Flowers occur in the axils of the upper leaves, two to three enclosed
in a spathe. Only male flowers are found in NZ.
- Fruit Fruits
not seen in NZ. Reproduction by regrowth from stem fragments.
- Leaves Very
dark green, up to 4 cm long, in whorls of four to six. Leaves
abruptly narrowed to a pointed tip.
- Stems Buoyant,
slender, brittle, 3 mm in diameter. Stems up to 1 m or more long,
much-branched, with nodes becoming closer together towards the
- Roots Bottom
Still, shallow, enriched
water in dams, ponds, drains, streams, rivers and lakes, in depths
of up to 5 m.
Abundant in Waikato
hydro lakes, scattered elsewhere in NI, and occasional, but spreading
in SI. Originally from South America.
Likely to spread to
new waterways. Listed on the National
Pest Plant Accord (see Introduction for details). The oxygen
weeds include Egeria, Elodea and Lagarosiphon.
In Egeria the leaves are dark green, in whorls of
four or five and 12-30 mm long. The flowers are white, conspicuous
and emerge above the water.
= after a Roman goddess of water; densa (Lat.) = dense.
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