Q How do I prune ornamental grasses?
A It depends on whether they're evergreen or deciduous grasses. The stems of deciduous ones, such as miscanthus, turn a pale-biscuit colour over winter and then the old stems are replaced by new green stems that grow from the base of the plant. Evergreen grasses, such as Festuca glauca, stay the same colour all year, although they can look untidy during winter.
Caption: Ornamental grasses look beautiful in the border
Q How do I prune deciduous grasses such as miscanthus?
A In late winter (January or February) cut all the old stems back to ground level. Secateurs and hedge shears work well for this job. Alternatively you can use hedge trimmers and slice the stems into short sections that you then leave on the ground as a mulch.
Whichever tool you choose, be careful to avoid cutting the new green growth that is emerging from the base of the plant.
If you don't want to leave the old stems on the ground as a mulch, they can be chopped up and out in the compost heap or green-waste disposal bin.
Caption: Cut all the old stems of deciduous grass back to ground level in late winter
Q How do I prune evergreen grasses such as Stipa tenuissima?
A These will struggle or even die if you cut them back to ground level in late winter with the deciduous grasses. Instead wait until April or May and gently comb through the plant with gloved hands to remove any loose old leaves and seed heads.
If they get really messy and tired looking after a few years, you can cut them hard in late spring or early summer. They should start to grow back shortly afterwards.
Caption: Comb out the old leaves and seed heads from evergreen grasses