Prickly Lettuce
Lactuca serriola
Origin. Eurasia.
Distribution in Canberra Region. Widespread in woodlands and grasslands, especially pastures, disturbed, and roadside areas.
Dispersal. Seeds dispersed by wind, water, and animals.
General Description and Biology
An annual or biennial weed that seems to prefer shady places.
To 1.5 m high with poplar-shaped profile, a strong rather prickly stem (to 5 cm diameter) and strong taproot.
Lower leaves stem-clasping, deeply lobed or irregularly serrated, about 5 cm long, with prickles on the midrib underneath.
Upper leaves smaller, less divided, and held vertically in the north-south plane.
The inflorescence is a much-branched panicle with small flowers, green at first, turning yellow.
Though not highly invasive this weed can get control of large areas if left unchecked.
Control methods
a. Manual.
Best is to pull out the whole plant before it produces seed.
If simply cut off at the base, manually or with brushcutter, it is apt to grow again � though some die.
Large ones may need to be dug out with a mattock.
b. Chemical.
Wipe rosette with weedbrush containing glyphosate 33% in water.