How to Grow Rosemary in Pots and Garden Beds

Rosemary (Salvia rosmarinus) is a woody perennial herb native to the dry, rocky hillsides of the Mediterranean coast. It thrives in full sun, poor to moderately fertile soil with excellent drainage, and actually produces more intense flavor when slightly stressed by dry conditions. The most common cause of rosemary failure is overwatering and soil that stays too moist.

Site and Soil

Rosemary needs a minimum of 6 hours of direct sun per day. In partial shade it grows slowly, produces weak foliage, and becomes more susceptible to fungal disease. Drainage is the other non-negotiable requirement: rosemary in waterlogged soil develops root rot and dies, often within one wet season. In heavy clay soil, plant in a raised bed, on a mound, or in containers. pH should be in the range of 6.0 to 8.0: unlike ericaceous shrubs, rosemary tolerates slightly alkaline conditions.

Container Growing

Container rosemary performs well in a free-draining potting mix (standard potting mix with 25 to 30 percent added grit or perlite), a pot of at least 30 centimeters diameter, and a sunny position. Water thoroughly when the top half of the potting mix is dry, then allow to drain completely. In USDA zones 6 and below, move container rosemary to a frost-free but cool location in winter.

Harvesting and Pruning

Harvest by cutting stem tips back by up to one-third of the stem length. Regular harvesting keeps the plant compact and stimulates the fresh new growth that carries the most intense flavor. Prune once a year after flowering in late spring or early summer, removing spent flower stems and reducing the current season’s growth by up to one-third. Do not cut back into old, brown, leafless woody stem tissue: rosemary does not reliably regenerate from cuts into old wood.