Rosemary

Identity and food use

Kew accepts Salvia rosmarinus and lists Rosmarinus officinalis as a synonym. It records a Mediterranean native range. The RHS profile describes a variable evergreen shrub and many available selections and cultivars; its growing guide describes fresh or dried sprigs for seasoning meat, bread and other dishes. The name change does not show that every plant sold as rosemary shares a cultivar or chemotype.

Growing outdoors

RHS recommends sun and free-draining soil. Its species profile lists chalk, loam or sand; acid, alkaline or neutral pH; and hardiness H4 in the UK scheme, with a stated band of −10 to −5°C. H4 is a horticultural category, not a guaranteed survival threshold for a specimen, cultivar or site. The RHS guide separately says established shrubs in UK conditions may survive −8°C, while harsh frost and cold wind can damage or kill them. Drought tolerance applies to established plants; it does not establish an irrigation schedule or justify withholding water from young plants.

Containers and winter shelter

The RHS guide describes containers at least 30 cm wide and deep with drainage holes. Vulnerable pots may be sheltered from winter cold and wet, including in a greenhouse or porch. That is overwintering advice, not a heated greenhouse production protocol. Cuttings provide a propagation route.

Harvest and storage limits

RHS describes year-round picking and hanging sprigs in a dark, ventilated place to dry. The inspected guide supplies no measured drying endpoint or shelf life. The description does not establish safe infused oil or another preservation process.

Research status and gaps

The underlying plant account received a partial source review. Its review scope is described in the original plant article.

Cultivar-specific frost response, productive heat/humidity limits and greenhouse setpoints remain unestablished.

Drying moisture targets, storage duration and food-process validation remain unresolved.

RHS H4 and the guide’s −8°C established-shrub observation are UK source contexts, not cultivar-specific survival tests or a universal frost limit.