Prickly sow-thistle – Sonchus asper

Sonchus asper

Sonchus asper

Sonchus asper (prickly sow-thistle) is an annual, seminiferous weed that has a strong, pivoting root and that produces latex. It prefers fresh soils that don’t lack limestone. It also needs to have fertile, clayey and clayey-sandy soils in order to prosper.

Common names: Sonchus asper, the prickly sow-thistle, rough milk thistle, spiny sowthistle, sharp-fringed sow thistle, or spiny-leaved sow thistle.


The stem is thick, hallow, hairless. It often has branches on its basal part. The height of the stem can be 80-cm.

Sonchus asper - cotyledon

The cotyledons have a spatula-like shape, or are oval-elongated, reddish and with short petioles.

Sonchus asper - cotyledon 1

The real leaves are thick and with thorny margins. The cotyledon leaves and the real leaves are covered by a waxed coating. This pest plant is commonly seen on cereal crops or on grasslands.

The first real leaf is serrated (lacy), the second real leaf has hairs on the serrated margins. The leaves have a blue to green color. The superior leaves are sessile and surround the stem at its base, in a spiral shape; these leaves also have hairs.

The flower is formed of convex flower heads, of a pale-yellow color (faded color). The flowers are grouped into dense inflorescences that have few flowers. The flower heads and the peduncles have no hairs.

Sonchus asper - flower

Sonchus asper - flower 1

The blossoming period is from summer time until autumn. The plant produces between 1000 to 6000 seeds.

How to fight this pest plant

The herbicides that are recommended when fighting the prickly sow-thistle are: Buctril Universal, Dicopur Top, Galera, Goal 4F, Kelvin Top.

Got a question?

Leave a Reply

Your email address will not be published. Required fields are marked *