How to Grow Rosemary: A Hardy Perennial Herb That Lasts

Rosemary comes from dry, rocky hillsides around the Mediterranean, and it has no tolerance for soggy soil. Almost every dead rosemary you see was killed by winter wet, or by being planted in heavy clay that never drains. The plant can survive frost, drought and neglect, but two weeks of waterlogged roots will finish it. So before you think about varieties or pruning, sort out drainage — that single decision matters more than everything else in this guide. If your soil holds water, plant on a mound or in a raised bed rather than at ground level.

Give rosemary full sun — six to eight hours a day — and the hottest, driest spot in the garden. It also needs shelter from cold, drying winds, so a south-facing wall or a sunny patio corner is ideal. If your soil is clay, dig in plenty of coarse grit or horticultural sand to open it up before planting. Plant in spring so the roots have a full season to settle before winter arrives. Space plants 60-90 cm apart, because rosemary grows into a substantial shrub and hates being crowded. Water it in well once, then leave it largely alone.

Once established, rosemary is drought-tolerant and usually needs no watering at all except in prolonged dry spells. Young plants need regular water through their first summer, but always let the soil dry out between waterings. Never feed rosemary with a rich, high-nitrogen fertiliser — it produces soft, floppy growth with weak flavour and poor cold tolerance. A light dose of general-purpose feed once in spring is plenty for container plants. In pots, use a gritty, free-draining compost mix and a container with a generous drainage hole.

Rosemary is naturally an upright shrub, and if you leave it alone it turns into a leggy plant with bare woody stems and leaves only at the tips. Trim it lightly every spring and again after flowering, taking the top few centimetres off each shoot. Always cut back into green, leafy growth, because rosemary rarely regrows from old bare wood — never cut into a thick brown branch and expect new shoots. Regular light trimming also gives you a constant supply of cuttings and cooking stems. Stop pruning by early autumn so new growth has time to harden before frost.

Hardiness varies hugely by variety: 'Arp' and 'Hill Hardy' cope with colder winters than the standard form, while 'Tuscan Blue' is best kept in a pot. The real killer is not cold on its own but cold plus wet — roots sitting in freezing water rot. In cold regions, grow rosemary in a pot and move it into a cool, bright, frost-free spot for winter; a cold greenhouse or an unheated porch is ideal. Do not bring it into a warm living room, where dry air and low light will weaken it badly. Outdoors, mulch around the base with grit rather than compost to keep the collar of the plant dry.

Snip stems at any time of year, because rosemary is evergreen and the leaves hold their oils right through winter. Take stems from the top and sides rather than the main framework, and never remove more than about a third of the plant in one go. For cooking, strip the needles from the woody stem and chop them; whole sprigs are excellent roasted with potatoes, lamb or chicken. The sturdy stems themselves make good skewers for kebabs. To dry rosemary, hang small bunches in a dark, airy place and strip the leaves once they turn brittle.