Nature · Ferns, grasses & other plants

Common reed

Perennial grass · to 4 m · flowers August–October

Phragmites australis — Poaceae

Common reed is the tallest grass in Britain and one of the most widely distributed flowering plants on Earth, forming the vast single-species reedbeds of the Norfolk Broads, the Somerset Levels and Leighton Moss. It spreads by rhizomes and stolons into pure stands that are the entire world of the bittern, the marsh harrier, the bearded tit and the reed warbler. It is also the thatcher's reed, and, cut and flooded, it is used to clean waste water.

How to spot them

▸The tallest British grass, reaching 4 m, in pure stands filling a whole wetland
▸Large soft feathery flower panicles, dark purple in August, fading to pale buff and persisting all winter
▸Broad grey-green leaf blades that swivel on the stem to lie downwind, so a reedbed hisses and combs in one direction
▸Stiff, hollow, pale straw stems still standing in midwinter after the leaves have gone
▸Freshwater and brackish margins: fen, broad, ditch and estuary

How to know it

The tallest grass native to Britain, reaching some four metres in a single-species stand

Common reed.

Its leaf blades swivel on the stem to lie downwind, so a whole bed combs and hisses in one direction

Common reed.

This one plant is the entire habitat of the bittern, the bearded tit and the marsh harrier

Common reed — reedbed is a priority habitat for all three.

Cut in winter after the leaves have fallen, it is the traditional material for thatching in Norfolk

Common reed — 'Norfolk reed'.

Planted in gravel beds, it is used to treat sewage and run-off, its rhizomes oxygenating the root zone

Common reed — hence constructed reedbed water treatment.

Feathery panicles are dark purple in late summer and bleach to pale buff, standing through the winter

Common reed.

In North America an introduced European lineage of it has become one of the continent's worst wetland invaders

Common reed — the native American subspecies is being displaced by it.

Quick-fire facts

•The tallest grass in Britain, growing to about 4 m
•Among the most widely distributed flowering plants in the world, on every continent except Antarctica
•Spreads clonally by rhizomes and above-ground stolons; some clones cover many hectares
•Reedbed is the key habitat for bittern, marsh harrier, bearded tit, reed warbler and reed bunting
•Flowers August to October; panicles are dark purple, fading to grey-brown
•Norfolk reed is cut in winter for thatch, a crop that requires the bed to be managed and re-cut
•Constructed reedbeds are widely used in tertiary sewage treatment and to clean contaminated run-off
•Uncut, a reedbed succeeds to scrub and then wet woodland, so the habitat depends on management
•An introduced European lineage is a notorious invasive in North American wetlands

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Sources

The Wildlife Trusts — Common reed