Carex riparia

Carex riparia is a perennial evergreen herbaceous clump-forming plant that thrives in damp to marshy areas. With a spreading bushy habit, its wide, long, rigid, glaucous green leaves reach 1m (3ft) in height with an 80cm (32in) spread. The inconspicuous flowering spikes that rise above the leaves are of no decorative interest. This sedge has trailing stolons that allow it to spread rapidly and colonise large areas. It is an invasive plant and is therefore useful when planted en masse to stabilise sunny banks of a body of water or a watercourse. However, its rapid spread can be a disadvantage in a small garden.

Carex riparia, also known as the river sedge, is widely found in wet areas and along waterways throughout Europe and Asia. It is an herbaceous species in the Cyperaceae family that can be quite invasive in marshy conditions. It is a tall carex with trigonous stems, meaning they have a triangular cross-section, and leaves that are 6 to 15mm (1in) wide and can reach up to 1.6m (5ft) in height. From May to July, the 3 to 10cm (1 to 4in) long spikelets, consisting of 3 to 5 brown, pointed, and flexible spikes, tower over the foliage. It is the quintessential perennial plant for riverbanks. This carex can be planted at a depth of 10cm (4in) in water. It also withstands temporary droughts.