Pruning Pampas Grass
When and how — Cortaderia selloana
Prune your pampas Grass in March — the optimal month is usually March.
The next pruning window is March next year.
When to prune?
The ornamental grass pampas Grass is pruned in March.
Cut ornamental grasses once a year, at exactly the right moment.
Ornamental grasses split into two groups with very different needs. Warm-season grasses (Miscanthus, Panicum, Pennisetum) die back above ground over winter and are cut down to about a fist's height in February or March. Those dry stems provide winter interest and protect the crown from frost and rain. Cool-season grasses (Stipa, Carex, Festuca, Deschampsia) stay green or semi-evergreen and must NOT be cut back hard — a spring tidy where you comb out the old dead blades with gloved hands is enough. Hard-prune a Stipa and whole tufts can rot out and die.
How to prune pampas Grass
Pampas grass requires only one serious prune each year, carried out in March before new growth emerges. This timing is critical: prune too early in winter and you remove the protective insulation the old foliage provides to the crown during cold snaps; leave it too late and you risk damaging fresh shoots. The old leaves and spent plumes look attractive through winter, providing structure and catching frost, so there's no need to rush. In March, cut back the entire clump to about 30–40 cm above ground level. Wear tough gloves, long sleeves, and eye protection—the leaf edges are razor-sharp and can cause nasty cuts. Use sturdy bypass secateurs for thinner stems or a pruning saw for older, thicker clumps. Some gardeners tie the foliage into a manageable bundle with string before cutting to make handling easier. If the clump is very large, hedge shears or even a powered trimmer can speed the job, though take care not to scalp the crown. Remove all the cut material from the garden; don't compost it unless your heap gets very hot, as seed heads can remain viable. After pruning, rake out any dead material trapped in the crown to improve air circulation and reduce the risk of rot. You may also remove any damaged or dead sections from the outer edge of the clump at this time. Pampas grass doesn't require deadheading or other pruning through the growing season—simply let it develop naturally and enjoy the spectacular plumes from late summer into autumn.
Common mistakes
✗ Cutting warm-season grasses down in October
You lose the winter silhouette AND the crown drowns without the protective dry stems. Wait until late February or early March, just before new growth starts.
✗ Hard-cutting cool-season grasses
Species like Stipa tenuissima and Festuca tolerate it poorly and may rot out. Combing with gloves is the right approach.
Too late this year? Here's what to do
Better to wait than prune at the wrong moment. The next optimal window is March next year. Until then: leave the plant alone — only remove dead or diseased wood (which you can do year-round).
