Herbariuma Backpackers project
All plants

Knotgrass

Polygonum aviculare

Family · Polygonaceae · Harmless

EdibleTraditional use
Knotgrass (Polygonum aviculare)Knotgrass (Polygonum aviculare)
GT1976, CC BY-SA 4.0 · Dalgial, CC BY-SA 3.0

The tough prostrate herb that grows in the middle of paths, in pavement joints and where cars drive over it. It takes being trodden every day and carries on, which almost no plant does.

Where it grows

Town and roadside · Roadsides and waste ground · Fields and pasture

Also known as

prostrate knotweed, birdweed

In flower

How to tell it

At each stem node there is a membranous, silvery, translucent sheath wrapping the stem like a paper ring: it is called an ochrea and is the mark of the whole family. Small alternate leaves. Tiny whitish or pinkish flowers in the axils.

What it is confused with

Field bindweed

Convolvulus arvensis

Harmless confusion

The common names get mixed up in several languages. Bindweed climbs and has funnel flowers several centimetres across; knotgrass is prostrate, does not climb, and has tiny flowers and the papery ochrea at each node.

Open sheet

What it is for

Young leaves eaten cooked, and an astringent infusion with a long European tradition. It is important food for seed-eating birds in late summer, hence one of the English names.

Traditionally used as food. This is not permission to eat it.

With documented traditional uses. Not a therapeutic indication and not a dose.

Sources