Pruning Red bistort 'Firetail'

Persicaria amplexicaulis 'Firetail' requires very little pruning, which is part of its appeal as a low-maintenance perennial. The main task is cutting back the old stems once flowering has finished and the foliage has died back. The best time to do this is in late autumn (November) after the first frosts have blackened the leaves, or in early spring (March or April) before new growth emerges. Many gardeners prefer to leave the spent flower spikes standing over winter; the dark seedheads provide structure and interest in the dormant garden and offer food and shelter for wildlife. When you do cut back, use a pair of sharp secateurs or garden shears to remove all the old stems down to ground level, just above the crown. The plant will reshoot vigorously from the base in spring. There's no need for complex shaping or thinning—simply clear away the previous year's growth in one go. If clumps become very large or start to encroach on neighbouring plants, you can lift and divide them in spring. Dig up the whole clump, split it into smaller sections using a spade or two forks back-to-back, and replant the healthiest portions, discarding any woody or exhausted central material. During the growing season, deadheading is not necessary. 'Firetail' produces a long succession of slim, bottlebrush-like red flower spikes from summer through to autumn, and they keep their colour well even as they fade, so there's no urgency to remove them for the sake of appearance or to encourage further blooms.