Common sowthistle – Sonchus oleraceus

Sonchus oleraceus

Sonchus oleraceus

Sonchus oleraceus (common sowthistle) is a seminiferous, annual weed, that has a pivoting root. This plant produces latex. It prefers soils that have humus, and that are rich in calcium and well-supplied with nutrients. The common sowthistle is often seen on crops and on grasslands what are well illuminated.

Common names: sowthistle, sow thistle, smooth sow thistle, annual sow thistle, hare’s colwort, hare’s thistle, milky tassel, milk thistle, soft thistle, or swinies.


The stem is straight, thick, branched. The height of the stem can range from 80 to 100 cm.

Sonchus oleraceus - plant

The cotyledons are round, with curved sides and flat lobes. The cotyledons are of a clear green color, with full margins and petioles.

Sonchus oleraceus - cotyledon

The real leaves are almost circular, lightly serrated. The following batch of leaves are sessile and their auricles are sharp. The leaves are pinnate or non-pinnate. The color of the leaves is blue-green. The leaves surround the stem and posses hairs.

The flower is a clear-yellow inflorescence, it can even have a yellow-green color. It is formed of convex flower heads and hairless, glandulous peduncles.

Sonchus oleraceus - flower

Sonchus oleraceus - flower 1

The blossoming period is the summer season and it can last until autumn. The plant produces between 4000 to 5000 seeds.

How to fight this pest plant

The herbicides that are recommended when fighting the common sowthistle are: Buctril Universal, Dicopur Top, Galera, Goal 4F, Kelvin Top.

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