Cutting back herbaceous perennials

How to do it

1. 1Wait, in most cases. Stems and seedheads left standing over winter feed birds, shelter insects and look far better in frost than bare soil — late February or early March is soon enough for the majority.
2. 2Cut early instead where the dead growth is a liability: anything that flopped into a wet mat, anything that had mildew or botrytis, and hellebores, whose old leaves carry leaf spot into the new flowers.
3. 3Cut to the ground for plants that die back completely (Hemerocallis, Aster, Phlox, herbaceous Paeonia), and to the lowest fresh basal shoots for the sub-shrubby ones (Penstemon, hardy Fuchsia, perennial Salvia) — those shoots are next year's plant and a cut below them kills it.
4. 4Use the same technique in summer for a second flush: shear Geranium, Nepeta, Erigeron and Alchemilla back hard straight after the first flowering, then water them, and they refoliate and flower again within weeks.
5. 5Leave evergreen and semi-evergreen perennials alone. Remove their tired individual leaves by hand instead of shearing the whole plant.
6. 6Compost what you cut, but keep out anything mildewed or spotted.

Plants that use it

Their calendar has a job that points to this guide.