Pruning Red valerian 'Albus'

Centranthus ruber 'Albus' benefits from two pruning sessions each year to keep it tidy, encourage repeat flowering, and prevent it becoming too woody at the base. The main prune takes place in March, just as new growth begins to emerge at ground level. Cut back all the previous year's stems to within 5–10 cm of the base, removing the old woody growth entirely. This hard prune rejuvenates the plant, promotes bushy new shoots, and prevents the centre from becoming bare and leggy. Use clean, sharp secateurs or garden shears for the job. The second prune comes in August, immediately after the first main flush of flowers fades. Shear back the spent flower stems by about half their length, cutting just above a set of leaves. This tidies the plant, stops it self-seeding everywhere (unless you want seedlings), and often triggers a second, smaller flush of white blooms in early autumn. If you prefer a more natural look or want to encourage wildlife, you can leave some spent heads for finches, which enjoy the seeds. Centranthus doesn't require complex pruning techniques—it's very forgiving. If you miss the August cut, simply remove any tatty or damaged stems as you notice them. Avoid autumn pruning after September, as the old stems provide some frost protection to the crown over winter. If the plant becomes very woody and sparse after several years despite regular pruning, it's often easier to replace it or allow self-sown seedlings to take over, as Centranthus is relatively short-lived, typically performing well for four to six years.