GRASSES, RUSHES & SEDGES
Use the sub tabs for specific grasses, rushes and sedges.
To many of us, all plants with long narrow leaves are grasses, but that is not technically the case. For clarification we turn to the RHS website and its technical editor Jon Ardle :
Grasses, from the family Poaceae, are one of the most successful plant groups on earth. They range from diminutive, fine-leaved fescues (Festuca), only a few centimetres high, to mighty bamboos many metres tall. Mankind depends on grasses: wheat, barley, rice, oats and sweetcorn are all grasses.
But not every plant with narrow, strap-like leaves is a member of the grass family. Calling all ornamental garden plants with narrow leaves ‘grasses’ is not only incorrect botanically, it can mislead the gardener when siting their plants. Most grasses prefer well-drained, dryish conditions and full sun, whereas most sedges, rushes and reeds like it moist. Some sedges and woodrushes will also thrive in fairly deep shade.
So, as narrow leaves are not a characteristic specific to grasses, other features such as the structure of flowers, stems, leaves and seedheads should be examined. As most of these plants are wind-pollinated, their flowers lack showy petals to attract insects and are often dull-coloured and bunched together into ‘spikes’. However, all share the characteristic that their narrow leaves grow from their bases rather than their tips – enabling them to keep growing, even if browsed by herbivores.
This latter point is significant. Keeping pruning most plants and they will die. Grasses, rushes and sedges, by growing from their bases rather than from their extremities, actually thrive the more they are cut. Rushes and sedges may look tatty if cut, but do not otherwise suffer. Grass on the other hand can be mowed often, its older growth at its tips being removed, and the main expanse looks even greener. The only draw back is that the seeds have less chance of reproducing.
To summarise using the words of an old rhyme : "Sedges have edges, rushes are round, grasses are hollow, so what have you found?"
And as Judith Garforth and Martha Boalch of the Woodland Trust put it :
Sedges form the Cyperaceae family. They have solid stems, normally with 3 defined edges in a triangular shape. Their leaves grown in three 'ranks' (this means that leaves grow on each of the three sides of the stem in vertical rows). The fruit is called an achene (a one seeded fruit that does not open to release the seed).
Rushes form the Juncaceae family. They have solid stems that are generally round. Their leaves tend to be clustered at the base rather than growing up the stem. The fruit is a many seeded capsule.
Grasses form the Poaceae family. Their stems are usually hollow (except at the nodes) and cylindrical. They have alternate leaves in two ranks (two vertical rows). The fruit is a one seeded grain.
RHS website : https://www.rhs.org.uk/plants/articles/misc/grass-sedge-rush
WILDLIFE TRUSTS : https://www.wildlifetrusts.org/wildlife-explorer/grasses-sedges-and-rushes The best identification website.
WOODLAND TRUST : https://naturescalendar.woodlandtrust.org.uk/blog/2021/how-to-identify-common-uk-grasses/
