MrsKinder retweetledi
Rosemary does not die of cold in most British gardens. It dies because someone cut into the old wood — and old wood never regenerates.
The rule is the same as for lavender: rosemary produces no new buds from brown wood. Every cut made below the green zone is permanent. That branch will not recover.
The main cut — after flowering, April to May in most of Britain:
Shorten the green stems by up to one third. Work across the whole plant to maintain a compact, domed shape. Always leave green tissue below every cut. The boundary between green and brown is the line you must not cross.
March — frost damage only:
After a hard winter, the tips may show 2–3 cm of blackened or grey dead growth. Remove only this. Nothing more.
September — light tidying only:
Trim the tips back by 1–2 cm to keep the shape compact before winter. No more than this. September cutting into green growth can leave wounds exposed to autumn wet and cold.
Never cut into brown wood at any time of year. If the green has retreated far from the main stems because the plant has been left unpruned for several years, there is no way to recover it. The plant will not regenerate from the base.
The three-way comparison worth understanding: a rose can be cut hard into old wood and will regenerate from dormant buds. Lawn grass regrows from its basal meristem regardless of how low it is cut. Rosemary does neither. It behaves more like lavender — prune annually while there is still plenty of green to work with, or lose the plant.
Regular kitchen harvesting is the easiest form of pruning. Every stem you cut for cooking is a cut that keeps the plant shapely and productive.
Five minutes with secateurs each spring = twenty years of rosemary. ✂️
English
