A tall plant, Rosebay willowherb is a successful coloniser; it can form dense stands of bright pink flower spikes on disturbed ground, such as woodland clearings, verges and waste ground.

The tightly packed, thistle-like purple flower heads of common knapweed bloom on all kinds of grasslands. Also regularly called black knapweed, this plant attracts clouds of butterflies.

Soft brome is a tall, annual grass of roadside verges, waste ground and meadows, and is a 'weed' of arable land. It has long, grey-green leaves and loosely clustered flower spikes.

The distinctive spiky, or 'bearded', green flower heads of wall barley appear from June to July and are easy to spot in an urban environment as they push their way up through pavements…

As its name suggests, pendulous sedge has drooping form with long, nodding flower spikes that give it an attractive and soft look. It can be found in wet woodlands and along riversides.

Great reedmace is familiar to many of us as the archetypal 'bulrush'. Look for its tall stems, sausage-like, brown flower heads and green, flat leaves at the water's edge in our…

Look out for the white, umbrella-like flower heads of lesser water-parsnip along the shallow margins of ditches, ponds, lakes and rivers. When crushed, it does, indeed, smell like parsnip!

On first glance, the meadow thistle looks a bit like a knapweed - it's not as prickly as other thistles and only carries one pinky-purple flower head. It can be found in damp meadows and…

Tansy is an aromatic plant of rough grassland, riverbanks and verges that has button-like, yellow flower heads. It is the main foodplant of the rare Tansy Beetle, now found at only two places in…

The brown, oval flower heads of ribwort plantain balance on top of thin, wiry stems; the resulting seed heads provide food for birds in winter. Look for this 'weed' in lawns, fields and…