Smooth Sow-thistle
Latin name
Sonchus oleraceus
Family
Asteraceae
Flowering season
March to November and all year round in mild winters.
English distribution
It is found throughout the country.
See the BSBI distribution map for Smooth Sow-thistle
Habitat
It is found on disturbed ground in grassland, brownfield sites
and waste tips, around ploughed fields, and alongside roads,
foot paths and coastal earth dykes.
It is a garden and agricultural weed.
Description
Smooth Sow-thistle is a very variable, annual herb that can
grow up to 2m.
Flowers are pale yellow (2-2.5cm across) in flower heads.
Leaves are variably prickly and have a greyish tinge (leaf 2).
They have pointed auricles at the site of attachment to the stems.
It is similar to Prickly Sow-thistle, which also appearing in March
in similar habitats, but it is generally more common, greyer and
with different auricles.
Both plants are variably prickly, ranging from few prickles to
prickly all over.
Usually, Prickly Sow-thistle has most prickles.
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Next page: Spotted Dead-nettle
Flowerhead
Seed clock
Leaf 1
Leaf 2
Pointed leaf auricles