[5][6] Carex vesicaria is a perennial plant with short creeping rhizomes which grow shoots resembling small tufts.

The narrow, ridged and pleated leaves can grow to around 1 m (3.3 ft) in length or more, and have fine toothed edges and sharp points.

[8] Many forms and varieties have been named, but no infraspecific taxa of Carex vesicaria are accepted in Kew's Plants of the World Online as of March 2020[update].

In Britain it has an altitude range of 0–455 m (0–1,493 ft) with the highest plants being found at Llyn Gorast in Cardiganshire.

[10] Carex vesicaria was cultivated in North America by indigenous people as its rhizomes were used for basketry,[6] The dried fibres, were sometimes used as thermal insulation in footwear in polar regions, are known as sennegrass, saennegrass or similar, from the plant's Bokmål name sennegras.