Prickly Lettuce (Lactuca serriola)

Photo: (c) Eigenes Werk CC0 1.0

Family: Asteraceae

Growth Habit: An erect plant which can grow up to 1.5 m in height but averages 80 cm with a reddish stem which is stiff, spiny and contains sticky white sap. Leaves are waxy grey green with fine spines along the veins and edges. The undersides have whitish veins. Leaves are oblong or lanceolate and lobed and get progressively smaller as they reach the top of the plant.

Type of Plant: Prickly Lettuce can be an annual herb or a biennial.

Photo: (c) Eigenes Werk CC0 1.0

Flowers: It has a yellow, daisy-like flower 11-13 mm wide, often tinged purple.

Photo: (c)-Matt-Levin-CC-BY-SA-2.0 (cropped)

Fruit/Seed: Seeds are produced in summer.

Dispersal: Seed is easily dispersed by wind as they have the typical daisy-family parachute of hairs, which are also found on plants such as dandelions.

Distribution: This weed may be found in gardens, roadsides, wastelands, cultivated areas and degraded pastures.

Status: Undeclared in Tasmania.

Weed Impact:

  • Minimal economic impact.
  • It can cause pulmonary emphysema in cattle feeding exclusively on the plant.

For further information contact the Department of Primary Industry, Parks, Water and Environment, Tasmania.

Control Methods:

  • Grubbing (all year). Ensure entire plant is removed especially the taproot.
  • Herbicide (summer, spring and autumn). Herbicides registered in Tasmania include dicamba, MCPA, glyphosate, 2,4-DB and 2,4-D.

N.B. Always check the herbicide label before use.