To make sure the fresh, new growth of these important yet greatly under-appreciated plants doesn’t grow into a tangled mass of old and damaged leaves, they need some pruning.
Small evergreen grasses, such as Festuca glauca, an evergreen clump-forming grass grown for its striking steel-blue foliage, are ideal candidates for an annual quick trim.
In summer and given the right growing conditions, it produces short blue-green flowerspikes, which gradually fade to an attractive buff colour.
Festuca glauca is best in full sun and on well-drained soil; in shade, it loses some of its blueness, and on wet ground it can rot, which is perhaps why it is often planted in gravel or containers where it can be assured of good drainage.
It can be trimmed in spring – simply remove any brown tips and cut back the dead leaves that collect around the base.
Larger evergreen species, such as Stipa gigantea, also need the dead leaves removing, with any remaining flower stalks dispatched to the compost bin.
Cut back Cortaderia selloana (pampas grass) as far as possible without trimming away too much new growth. Use thick gloves, because the leaves have sharp edges.
Some burn the old growth but unless you know exactly what you’re doing, leave the matches in the box and hand-prune with shears or secateurs.
Most deciduous grasses, such as Stipa tenuissima, can be trimmed to ground level before new growth starts to appear.
And old stems of Miscanthus, for example Miscanthus sinensis ‘Septemberrot’, a deciduous grass growing to a height of more than six feet – should have old stems and dead growth removed at the end of this month or early in April.
Grasses such as sedges (Carex and Luzula) are not cut back completely. Spent flowering stalks can be cut off, and any unsightly scorched or diseased leaves can be removed individually.
Once the clump outgrows its space, lift and divide it like any other perennial. Debris can be removed, the area tidied, and a mulch and fertiliser applied.