Knotgrass
Knotgrass colonising bare ground
Flowering stem
Red and white flowers - same stems
Close-up of white flowers
Close-up of pink flowers
Flowering stems with fruits
Dark fruits protruding from flowers
Leaves of differing size
Polygonum aviculare
Polygonaceae
June to November
It is found throughout the country.
See the BSBI distribution map for Knotgrass
It grows on bare ground in wasteland and by the sea and
as a weed of cultivated land.
Knotgrass is a native, annual, spreading, prostrate herb,
growing between 5cm and 1m.
Flowers are in groups of 3 to 6 and may be white, pink or
red – sometimes on the same plant.
There are 4-8 stamens and 2-3 styles.
The tepals (perianth segments) are fused for below half
their length.
Fruits are triangular and are either hidden by or poke out
from the flowers.
Leaves are up to 5cm (usually less) and vary from elliptic-
lanceolate to linear.
Leaves on the main stem are 2 to 3 times bigger than
those on flowering stems.
Previous page: Knapweed Broomrape
Next page: Lady's Bedstraw
Knotgrass colonising bare ground
Flowering stem
Red and white flowers - same stems
Close-up of white flowers
Close-up of pink flowers
Flowering stems with fruits
Dark fruits protruding from flowers
Leaves of differing size
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