Rosemary
Salvia rosmarinus
Other names: Rosmarinus officinalis (former botanical name)
Rosemary is an evergreen Mediterranean shrub with needle-like, aromatic leaves and small blue flowers that bees visit in late winter and spring. It is drought-tolerant and long-lived in mild climates. In colder regions it grows well in a pot that is moved under cover for winter.
How to grow rosemary
Light
Full sun, with six to eight hours of direct light. Indoors it needs the brightest window available.
Watering
Water young plants regularly until established. After that, let the soil dry between waterings. Rosemary in pots must never sit in a saucer of water, yet should not dry out completely either.
Soil and feeding
Grow in lean, fast-draining soil. Add grit or sand to heavy ground. Fertilizer is rarely needed.
Planting and pruning
Trim lightly after flowering to keep plants bushy, and harvest sprigs at any time. Do not cut back into bare wood. In zones 7 and colder, choose hardy varieties such as 'Arp' or bring potted plants into a cool, bright room before hard frost.
Propagation
Take 3 to 4 in (8–10 cm) cuttings of soft new growth in late spring, strip the lower leaves and root them in gritty mix.
Common problems
- Needles turn brown from the tips
- Root rot from wet soil is the usual cause. In pots, a completely dry root ball looks the same. Check the soil before watering.
- White powder on leaves indoors
- Powdery mildew from still, humid air. Increase air flow and light.
- Plant dies over winter
- Cold combined with wet soil. Improve drainage and shelter the plant from freezing wind.
Questions about rosemary
Can rosemary survive winter outdoors?
It is reliably hardy in zones 8 to 10. Hardy varieties survive in zone 7 and sometimes zone 6 with sharp drainage and shelter.
Why is rosemary now called Salvia?
DNA studies showed that rosemary belongs within the sage genus, so botanists renamed it Salvia rosmarinus in 2017. The old name, Rosmarinus officinalis, is still widely used.
Plant details
| Botanical name | Salvia rosmarinus |
|---|---|
| Family | Lamiaceae |
| Native range | Mediterranean coast |
| Plant type | Herbs. Evergreen shrub |
| Soil | Sandy or gravelly, sharply drained soil |
| Flower color | Blue |
