BASF Agricultural Solutions UK

Prickly sow-thistle

(sonchus asper)

Young plant

The cotyledons are oval and short stalked. The first true leaves are edged with backward-pointing teeth, and the overall shape that of a rounded diamond. The leaf is a dull blue green colour and the edge may be tinged with purple.

Mature Plant

The branched stem is smooth and hollow. The leaves are a glossy rich green and clasp the stem with rounded bases.


Flowerheads are pale yellow, 20-25mm across, and form loose clusters. Petals are reddish-grey beneath. The base of the flowerhead is flask -shaped, becoming more pronounced as it grows older.

Height 120cm

Prickly sow-thistle Profile

Key feature- Leaves are glossy and have sharp prickly edges and rounded bases that clasp the stem
- taproot
- Mid yellow flowers
Number of seeds produced per plant5,000
Seed shedMay-October
Germination periodMarch-July and September to November
Germination depth5 cm
Primary dormancyLow
Does it have a secondary dormancy?Yes
Seed longevity>5 years
Factor promoting germinationLight
Rate of seed decline with cultivationsHigh
LifecyclePlants which germinate in autumn overwinter as rosettes, producing flowers in May/june; plants germinating in spring flower in June. The latter can set seed in 10 weeks. Prickly sow-thistle only reproduces by seed and is distributed by wind
Geographical LocationWidespread in England and Wales
Soil TypeNitrogen rich loams or nutrient rich sandy and stoney soils which are not too dry
ImpactIncreasing found in arable rotations particularly in winter crops. Autumn germinating plants can overwinter as rosettes and flower in May, spring germinating plants flower in June
5% yield loss from 50 plants per m2
Resistance riskNo resistance in the UK but populations resistant to ALS herbicides in France, Norway, USA and Canada
Spray application

Spray application

Find out what our expert, Tom Robinson advises when it comes to spray application.

Cultivation principles

Cultivation principles

Philip Wright talks on cultivation principles.

Chemical control

Chemical control

Stuart Kevis and Iain Ford talk on chemical control.



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