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Book cover - Common Weeds of New ZealandAn Illustrated Guide to
Common Weeds
of New Zealand


Conium maculatum


Reproduced from
Common Weeds of New Zealand
by Ian Popay, Paul Champion & Trevor James
ISBN 0 473 09760 5
by kind permission of the
New 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.
Appropriate acknowledgement of the publication Common Weeds of New Zealand must always be given.

Available from Nationwide Book Distributors

Conium maculatum - hemlock Conium maculatum - hemlock

Tall, branching, foul-smelling, ferny leaved, hairless annual or biennial, with purple spots on leaves and stem. Small flowers in white umbels at the top of stems up to 2 m tall.

  • Flowers Small, white, 2 mm in diameter, in large terminal compound umbels up to 8 cm in diameter. Flowers Sep-Jan.
  • Fruit Dark brown barrel-shaped capsules 3 mm in diameter, with light brown wavy ridges.
  • Leaves Large, alternate, dark green on the upper surface, grey-green underneath. Fern-like, two to three times pinnately divided, deeply lobed, egg-shaped final leaflets up to 40 mm long.
  • Stems Smooth, hollow, branching, blue-green. Conspicuously spotted or blotched purple or pink.
  • Roots Woody taproot.


Road-sides, river-beds and banks, hedgerows, forest margins, damp or marshy places and waste places.


Common throughout NI and in SI especially Otago and Southland, only occasionally found in Westland. Occasional on Stewart and Chatham Islands. Originally from Europe, Asia and north Africa.


Conium maculatum - hemlockPlant dies after flowering. All parts are very poisonous even when dry. Animals tend not to graze the plant because of its unpleasant smell. Reputedly the plant with which Socrates was forced to commit suicide. Subject to Pest Plant Management Strategies in several regions of NZ. Details are available from individual regional councils or unitary authorities.

Derivation of botanical name

Conium (Gr.) = hemlock; maculatum (Lat.) = spotted.


Web-notes: Weed Links

On this site

Reproduced from Common Weeds of New Zealand:

External Links

WeedbustersWeedbusters 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.
Weed keyNew Zealand Weeds Key
An interactive identification key to the weeds of New Zealand. Developed at Landcare Research.

New Zealand Plant Conservation Network naturalised plants
Search for information on more than 2500 naturalised and weedy plants.
NZ Plant Protection SocietyNew 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."
Massey UniversityMassey 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.

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Last updated: March 1, 2021