How to Grow Rosemary

Overview

Rosemary is a hardy, evergreen Mediterranean herb that thrives in home gardens once established. Its aromatic, needle-like leaves are essential in roast dinners and Mediterranean cooking. Rosemary also produces beautiful blue flowers in spring that are loved by pollinators. It can live for many years, growing into an attractive shrub.

Health Benefits

Carnosic acid for brain health: Rosemary contains carnosic acid, a compound that may help protect brain cells and has been studied for its potential to support memory and concentration.

Anti-inflammatory properties: The rosmarinic acid and other compounds in rosemary may help reduce inflammation, and rosemary has a long history of use in traditional herbal medicine.

Iron and calcium: Rosemary provides useful amounts of iron and calcium, supporting energy levels and bone health. Even small amounts used regularly in cooking can contribute to your nutrient intake.

Soil Preparation

Rosemary demands well-drained soil and will not tolerate waterlogging, which causes root rot. Sandy or gravelly soils in a sunny, sheltered position are ideal. If you have heavy clay, grow rosemary in raised beds or large terracotta pots with gritty compost. The ideal pH is 6.0 to 7.5. Poor soil is actually preferable to overly rich ground, which produces lush but less aromatic growth.

Sowing & Planting

Rosemary is best bought as young plants or propagated from semi-ripe cuttings in late summer. Take 10cm cuttings from non-flowering shoots, strip the lower leaves, and root in gritty compost. Plant out from March to May, spacing 60cm apart. Seeds can be sown indoors in spring but germination is slow and erratic.

Care & Maintenance

Water sparingly once established, as rosemary is drought-tolerant and prefers dry conditions. Prune lightly after flowering in spring, removing leggy growth to maintain shape. Avoid cutting into old wood, which may not regrow. Feed container-grown plants occasionally with a dilute liquid fertiliser. In very cold areas, protect with fleece in severe winters.

Harvesting

Pick sprigs year-round as needed, as rosemary is evergreen and always available. The flavour is strongest just before flowering in spring. Cut sprigs with secateurs rather than tearing, which can damage the plant. Use fresh or dry by hanging bundles upside down in a warm, airy place.

Common Problems

Root rot is the primary killer, caused by waterlogged soil in winter. Ensure excellent drainage and avoid overwatering.

Rosemary beetle has metallic green and purple stripes and feeds on leaves. Pick off by hand and shake branches over a sheet to collect them.

Die-back can occur in very cold winters, especially in exposed gardens. Provide winter protection with fleece and plant against a warm, south-facing wall.

Companion Planting

Rosemary is a good companion for carrots, beans, and cabbages, as its strong aroma can help deter carrot fly and cabbage moth. Rosemary has no significant plants to avoid and adds beneficial habitat for pollinators.