Removing old and dead foliage

While the leaves stay green they are still photosynthesising and moving food back down into the crown, rhizome, root or bulb to build up next year's growth and flowers. Cutting them off too soon starves that store, which weakens the plant and, on bulbs, causes poor flowering or blindness the following spring. Once the foliage has yellowed it has finished feeding the plant, so clearing it then does no harm and instead removes cover for slugs, tidies the plant, and takes away tired growth that can carry pests and disease into winter. On ferns, leaving the old fronds a little longer also blankets and protects the crown from frost.

When

Wait until the leaves have done their job before you cut anything. On plants that die back to a crown, rhizome or root, this means leaving the foliage in place until it has turned yellow or brown and started to collapse of its own accord, usually in autumn or early winter. Cut asparagus ferns right down once they yellow in autumn. Leave the old fronds on hardy ferns over winter and cut them off in early spring, just as the new croziers start to unfurl, so the tatty top growth shelters the crown through the cold. Let dying bulb foliage (daffodils, tulips, bluebells) fade naturally for about six weeks after flowering before removing it. Clear rhubarb, celeriac, bugle and similar as their outer leaves go over. Pull off any single dead or diseased leaf whenever you spot it, at any time of year.

How

Wait for the leaf or frond to yellow and soften first. Where it comes away with a gentle tug, simply pull or twist it off at the base and drop it in the compost or green waste. Where it does not pull cleanly, cut it with clean secateurs or a knife close to the crown, rhizome or root, taking care not to nick the growing point or any fresh shoots pushing up. On asparagus, cut all the ferny stems down to just above ground level once they turn yellow. On hardy ferns, snip the old fronds off in spring above the tight new croziers. On bulbs, only remove foliage once it has gone yellow and limp; do not tie or knot the leaves to tidy them, as this stops them feeding the bulb. Rake or gather up the cleared material, keep anything diseased out of the compost, and finish by mulching the crown with compost or well-rotted manure.

Notes

It covers any plant that retreats to a crown, rhizome or root and needs its old foliage clearing: asparagus ferns, hardy ferns, bugle, celeriac, rhubarb and dying bulb foliage. The single most important rule across all of them is to let the foliage yellow and finish feeding the plant before you cut it, rather than tidying it away while still green. The variations to hold in mind: asparagus is cut to the ground in autumn once yellow; hardy ferns keep their old fronds through winter and are cut in spring for crown protection; bulbs need roughly six weeks of dying-down and must never be tied or knotted; and a diseased leaf can be removed at any time. Rhubarb leaves are poisonous even though the stalks are not.