Bladder Sedge has shortly creeping rhizomes and it can be a tall species, reaching up to 120 cm in height. This species has triangular stems that are rough towards the top but not lower down, and its narrow leaves are rigid and with fine toothed edges. Bladder Sedge flowers from May to June and it is very similar to Bottle Sedge, so care should be taken when separating these species!
Bladder Sedge occurs in wet habitats, such as by lakes, rivers, streams, ponds and canals. This species can also be found in flooding marshes and ditches, wet meadows and wet woodland, often in sites inundated in spring and dry during summer. It can also colonise wet pockets in disused areas such as clay or gravel pits.
Distribution and threats
Bladder Sedge has been lost from many sites in England and S.E. Ireland, and it is listed as Vulnerable in England’s Red List and as Scarce in Oxfordshire. The causes of its decline in Britain include drainage, falling water tables, ditch cleaning and eutrophication. In Oxford Bladder sedge is found especially near Otmoor and the Ray, mainly on Oxford clay.