Pruning Cotton lavender

Cotton lavender requires pruning twice a year to maintain its compact, silvery mound and prevent it becoming woody and bare at the base. The main prune takes place in April, just as new growth begins to emerge. Using clean, sharp secateurs or shears, cut back all the previous year's growth by about one-third to one-half, shaping the plant into a neat dome. Aim to cut into green, leafy growth rather than old brown wood, as santolina is reluctant to regenerate from bare stems. This spring prune encourages dense, bushy foliage and keeps the plant tidy. The second prune comes in August, immediately after the yellow button flowers fade. Shear off the spent flower heads and the top few centimetres of foliage. This light trim tidies the plant, prevents self-seeding, and promotes a fresh flush of silver-grey leaves that will carry the plant attractively through autumn and winter. If you prefer the architectural look of the dried seed heads, you can delay this August prune until early spring, though the plant may look slightly untidy over winter. Never cut hard back into completely bare, woody stems, as cotton lavender rarely resprouts from old wood. If your plant has become leggy or gappy despite regular pruning, it is usually better to replace it than attempt drastic renovation. Cotton lavender is relatively short-lived—typically five to eight years—and older specimens often lose vigour. Pruning keeps young plants dense and attractive, but cannot indefinitely rejuvenate neglected or aged shrubs.