04-June London’s Sedges: June’s Unsung Wonders

Summary

Beneath London’s bustling surface lies a quiet botanical marvel—sedges. These unassuming plants, with their triangular stems and subtle blooms, thrive in the city’s wetlands, woodlands, and even sandy soils. Discover the pendulous sedge’s graceful droop, the carnation sedge’s rare beauty, and the ginger-flavored roots once savored by Henry VIII. Return on 04 June to uncover the overlooked elegance of London’s sedges.

Article

Sedges

Early summer is the best time to get to know sedges as the majority of the fifty or more in London are mostly in flower or fruit. These flowering plants often get missed or ignored as they have no flamboyantly coloured petals or sepals just tiny floral parts hidden away in either a compressed usually dull-coloured flowerhead or attached catkin-like to the flower stem. Fortunately the arrangement of flowers on a flowerhead is highly variable. They can be either compressed at the end of a spike, branched, pointing upwards, downwards or hanging as they often do in clusters. Although a definitive identification often involves looking at their fruits their various different flower arrangements allows for some field identification. Many look like grasses e.g. the cotton grasses Eriophorum spp. and others like rushes e.g. the spike-rushes Eleocharis spp. club rushes Scirpus spp. and bulrushes Schoenoplectus. The largest and most typical group are the true sedges Carex spp. If confused, one way of helping to identify a sedge is to roll its stem between your thumb and finger. As many are distinctly triangular in cross-section you can often feel the three edges.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

Most sedges show a distinct preference for wet, impoverished soils and so should be looked for in marshes, bogs, wet meadows, wet woods and by the edges of ponds, lakes and rivers. The few that do prefer drier sandier soils can be found in dry pasture, heath or along the sandy edges of the estuary. Adding fertiliser or draining land soon sees most sedges disappear. They often have tough, coarse leaves which provide little nutriment to cattle which consequently usually avoid them. However, typically man has found other uses such as drying their leaves and stems to make baskets, thatch roofs and even to wrap around wine bottles. More recently it has been discovered they can be good ecological indicators e.g. the thin-spiked wood sedge C. strigosa indicating ancient woodland and the brown sedge C. disticha indicating old flood meadows.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

The most noticeable and widely seen sedge in London is likely to be the pendulous sedge C.pendula due to its large size (up to 70 cms wide and 1.8 m high) and long, gracefully drooping catkin-like flowerheads. It is so popular it is commonly seen in gardens and even planted around one of the ponds on Clapham common as an ornamental. It is less often seen in the wild but can still be found in Lesnes Abbey woods.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

Another common sedge is to be seen on any walk on chalk downland. This is the glaucous sedge C. flacca which can often be picked out by its bluish leaves. In woods, the wood sedge C. sylvatica has bright green leaves and long stalked flowerheads that tend to get noticed beside paths and it is often the only sedge to be found. In more boggy areas you might expect to see the silky snow-white cotton flowerheads of the cotton grasses. In Dickens’ time the whole of the north Kent marshes, which he often walked through, were probably covered in these dazzling white flowers. Now there are so few boggy areas left in London they take a bit of finding in either Epping forest or on Keston Common.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

In drier, more sandy situations you might expect to see either the spring, pill or sand sedge. The earliest to flower is the spring sedge C. caryophyllea (5-15 cms) which has red-brown club-shaped flowerheads and can also be found on roadsides and in dry ditches. The pill sedge C. pilulifera is larger (up to 30 cms) and has more egg-shaped flowerheads reminiscent to some of medicinal pills. The largest is the sand sedge C. arenaria (up to 40 cms) which is usually noticed as a line of plants joined by one rhizome binding the loose soil it grows in together. All three are also sedges of dry heathland.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

Around some ponds you may come across the common spike rush Eleocharis palustris. Like other spike rushes its flowers are compressed into arrow-like tips at the end of its stems. It can be found in Frays farm meadows. The remote sedge C. remota shows a preference for alderwoods and the edges of spring-fed streams within them. It has bright green leaves and stalkless well separated flowerheads. The bristle club rush Isolepis setacea with its compact flowerheads set along its stems rather than at their ends has an odd habitat preference. It is often found where cattle have left their hoofprints in muddy fields or even where humans have left theirs along woodland paths.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

Few sedges can be called beautiful but the black, cyperus and great pond sedge are exceptions. Fortunately the black sedge C. nigra is very common. It has bluish-green leaves and neat upright flowerheads with each black spike having a central green midrib and clear membranous edge combining together to produce a highly attractive pattern. The cyperus sedge C. pseudocyperus is first noticed for its unusual yellow-green foliage and then its clusters of neat bristly flowerheads. These are uncomfortable to touch as are its sharply-edged leaves. However, its roots which taste of ginger could well have been eaten at Nonsuch palace when Henry the eighth lived there. It can still be found today growing in Nonsuch park. The great pond sedge C. riparia always attracts attention when it grows in dense patches beside water, especially if its flowerheads are covered in buttery yellow anthers. It can be found at Yeading Brook fields.

Other sedges that may well get noticed this month are the false fox sedge, carnation and hammer sedge. The false fox sedge C. otrubae forms dense tufts up to a metre high beside roads, hedges and ditches. It produces dense clusters of persistent yellowish-green flowers which have a spiky appearance. It can be found in Perivale wood. The carnation sedge C. panicea is a little smaller and a lot rarer but is worth looking for in damp meadows. It gets its name from its blue-green leaves so similar in colour to those of true carnations. The hammer sedge C. hirta occasionally forms large noticeable patches in parts of Walthamstow marshes. It is easier than most to identify as it has hairy leaves, a character not at all common in sedges.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image

Some of the easiest of all sedges to identify in the field are now sadly gone. The flea sedge C.pulicaris had flowers uncannily like fleas and the star sedge C. echinata flowers that were perfectly star-shaped. The unusually named starved wood sedge C. depauperata was called at one time London’s rarest sedge. It is believed it hung on in a wood in Charlton till it was stolen by, of all people, a botanist wanting to complete his herbarium.

04-June London’s Sedges: June’s Unsung Wonders Section Image

04-June London’s Sedges: June’s Unsung Wonders Section Image