• Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Sow thistle is a soft, slightly fleshy, leafy annual. The winter-growing rosette sends up a leafy stem up to 1m tall, with milky sap and yellow flowers about 2 cm in diameter
  • Leaves are sharply pointed but are never prickly
  • Flower heads are pale yellow, composite, up to 2cm across, in clusters of a few or many
  • Leaves on the flower stem alternate on two sides of the stem and are soft, mid- to dark-green and are hairless. Leaves are flat or slightly wavy and are divided nearly to the midrib into sharp, regular lobes. The basal lobes of the stem leaves are sharply pointed and spreading, and the terminal lobes are broad and pointed. Arrow-shaped ear-like projections wrap around the stem at the base of the leaf stalks
  • Flower stems are erect, hollow, finely ribbed and hairless, leafy, branched and have milky sap
    Plants are found throughout New Zealand, in a wide range of places including gardens and disturbed ground, cultivated fields, waste areas and grasslands

  • Prickly sow thistle is similar in most respects except the leaves are tougher and have prickly spines on the lobed leaves and the flowers a more golden yellow. It can also be an annual or biennial plant.


  • These species are very widespread, found in Europe, North Africa and in north and west Asia, and has been introduced to many other parts of the world.

Life cycle

  • Both sow thistles are prolific producers of seeds and a single plant can produce up to 25,000 seeds
  • Each seed has a pappus (feathery attachment) which helps it to be carried for some distance by air currents
  • Seeds like to germinate on or near the surface and can germinate at any time of the year if soil moisture is adequate. Seeds can survive in the soil for at least a year or two
  • Plants first produce a low-growing rosette which, in the spring, sends up a flowering shoot.


  • Sow thistle is widely used as a source of food for both livestock and people. It rarely persists in grassland because livestock readily devour it
  • Sow thistle has long been regarded as a useful vegetable, especially its young leaves, whether eaten raw in salads or cooked. In New Zealand it is known as puha
  • Due to its nature, prickly sow thistle is less favoured for food.

Impact on pasture

  • This weed has very little effect on pasture as it is readily grazed by stock

Impact on crops

  • this weed can grow into a tall, bushy plant, but is easy to control by mechanical or chemical means

Grazing Management

  • Readily grazed by cattle

Physical control

  • Easily controlled mechanically and, when young, easy to pull or hoe out.

Chemical control

  • Readily controlled by all commonly used herbicides except trifluralin

Harrington, KC 2016. Sow thistle. Massey University Weeds Database (accessed 23 June 2017).

Popay I, Champion P, James, T 2010. An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.