Although the term "reeds" is often used to describe a wide variety of waterside or emergent vegetation the term should be applied more properly to the common reed (Phragmites australis). This giant of grasses can be found in many places where there are coastal or inland water bodies. Common reed, with its bamboo-like stems and leaves branching off at intervals, is the largest native grass and the tallest non-woody species in the British flora, reaching up to 3 metres (10 ft.) in height. It is extremely vigorous, often occurring as a pure stand by completely excluding other plants. It can thus be a very distinctive feature where it occurs in quantity. On Tollesbury Wick the largest area is in Pier Fleet, near to the old Railway line, but smaller amounts can be seen in other fleets and the borrowdyke. Because of its dominance, there are few other plants associated with reed beds, but there are several other species which utilise the habitat, and some are of national conservation concern such as water vole, bearded tit, bittern, reed bunting, water rail, marsh harrier and the moths reed leopard, dotted footman and Webb's wainscot. However, by no means all of these are likely to be found at Tollesbury Wick.

Common reed is said to be one of the world's most widely-distributed plants. It is found in 89% of European territories and is virtually cosmopolitan in temperate regions of the world, but uncommon in the tropics. It is less abundant in the USA and usually considered to be a serious pest in waterways. The universal success of common reed is, in part, due to its tolerance of a wide range of water depth (up to 2 metres in still water) and some degree of salinity. Its competitive ability arises from an extensive network of underground root-like stems (rhizomes) which can expand at a rate of 1 to 2 metres per year. These then throw up vertical stems at regular intervals which can grow at a rate of 10 cm per day! In addition, further plants can establish from small detached pieces carried along the waterway. The largest reedbed in the UK is 4l0 hectares (1025 acres) in the tidal Tay Estuary in Scotland, while the largest inland reedbed is [46ha (365ac) at Minsmere, in Suffolk. A 1979 RSPB survey (Everett 1989) showed that the most extensive reedbeds were in East Anglia. However, an updated survey in 1993 (Hawke 1996) showed that the majority of 926 sites in the UK were fragmented into areas of less than lha. Currently Norfolk has 1542ha, Suffolk 550ha and Essex only 135ha. The two largest in Essex being Langenhoe (54ha) and Old Hall Marshes (l9ha).  Reedbeds are one of the key wildlife habitats to have a Habitat Action Plan costed under the UK's Biodiversity Action Plan. There are a number of large projects underway to re-create reedbeds including Lackenheath Fen in Suffolk and Otmoor in Oxfordshire, at the Avalon Marshes, west of Glastonbury, and three large beds in the Cotswold Water Park. Moderate areas of reed have also been established at a newly-created Wildfowl & Wetland Trust reserve on a redundant reservoir site at Barn Elms in West London.
So, although reed beds have declined in recent years, due to increased wetland drainage, it seems likely that their future is reasonably assured; as they will be at Tollesbury Wick.