When to plant rosemary?

When, by region

March, April and May, the several years before a harvest, 10 cm (4 in), 45 cm (18 in), a pot of 30 cm (1 ft), 25 per cent grit, -8 °C (18 °F) and replacement every 7 or 8 years are from the RHS. May in a pot is from the herbs-in-containers page. Autumn or the end of winter, cuttings of about 15 cm (6 in), 15,000-20,000 plants per hectare, the 5-6 years and the 10 years are from Campania. Sicily has no rosemary chapter. Umbria 2025 does not name it. Thyme, which wants the same conditions, is in when to plant thyme. The months are in the February calendar, March, April, May, September, October and November.

March, April and May

The RHS sows indoors in spring, and the calendar marks March, April and May. From seed to a first cut takes several years: a bought plant, or a cutting, is quicker. Plant out in the same three months, once the soil starts to warm. Harden off the indoor ones and move them once they are at least 10 cm (4 in) tall. A plant bought in a pot can go in during other months, but spring remains the best time.

On the herbs-in-containers page, rosemary, sage, mint, oregano and thyme are sown indoors, or outdoors in May in containers. The pot is in starting seeds indoors.

Campania, autumn or the end of winter

In Campania the transplant goes in during autumn or at the end of winter, on ground prepared with no waterlogging. Start from plants raised from cuttings or from seed. Cuttings, about 15 cm (6 in) long, are set to root in a nursery at the start of spring or the start of autumn. A cutting gives plants identical to the parent, and a stronger root system than seed. The density is 15,000-20,000 plants per hectare. The distance between rows follows mechanical weed control. A measurement in centimetres is not written. A watering at planting helps them settle.

It is an evergreen shrub, and it stays out of very cold, damp climates. The crop lasts 5-6 years on average, and can reach 10. If the whole top is cut, the cut stays about 25-30 cm (10-12 in) above the soil. Sicily has no rosemary chapter. Umbria, in 2025, does not name it. Sage, on the same Campania date, is in when to plant sage.

Dry, not sodden

Plant in the sun, in light soil that drains. If the ground is heavy and stays wet in winter, the RHS puts it in a raised bed or a pot. In the ground, at least 45 cm (18 in) apart, without burying the crown of the roots. In a pot, one in at least 30 cm (1 ft) wide and deep, with up to 25 per cent grit. In the first year, water during dry spells. After that, in the ground, it barely needs water. A pot does, once the compost dries, without leaving it sodden: in winter the roots rot. Well-rooted plants on soil that drains cope down to -8 °C (18 °F). In a hard frost with a cold wind, cover them. The pot is in the container garden.

Replace it every 7 or 8 years, because even with pruning the bush goes bare at the base and does not reshoot from old wood. Take softwood cuttings in late spring or summer, semi-ripe cuttings in summer, and layer in spring or autumn. Trim after flowering, without cutting into old wood. Pick the leaves all year: the best flavour is on the new growth, in late spring and summer. The RHS marks it as a high-risk host of Xylella fastidiosa, and writes that British-grown plants reduce the risk of importing the disease. In crop rotation perennials stay outside the plan, in a permanent corner. Rosemary is one of those.