If you live in a frost-free area, you can grow rosemary in your outdoor garden all year round. Rosemary needs a place in full sun, with about 6-8 hours of full sunlight and a sandy, well-drained soil that has been amended with lime. Established plants can survive for many years if left undisturbed and make excellent borders and hedges that require infrequent pruning. It cannot over-winter in cold climates so you will have to grow your Rosemary indoors in a container so you can bring them indoor over the winter. Bring the plants indoors at least several weeks before first frost date. Move them back outdoors in spring once all danger of frost has past. Water and feed potted rosemary regularly. When grown in pots, it is best kept trimmed to stop it getting too straggly and unsightly. Repot at least once a year. Spring is a good time to repot your rosemary, but it should be fine no matter what time of year you get to it.
Propagate Rosemary from cuttings of the twisted wood of non-flowering branches in early summer, or layer established branches. Rosemary can also be grown from seeds but they germinate slow and difficult and often don’t grow true to their parent. Sow seeds in April but expect low germination rates. It’s much faster to start with cuttings and you will be sure of what type of plant you will get. Place the cutting in a small pot filled with potting compost. Stand the pot in water to enable the compost to draw water up. Once the compost is moist place the pot in a propagator or cover the pot with a clear plastic bottle to retain heat. The cutting should develop roots and be ready for transplanting about 2 months after the cutting. Plants can be set out in the spring when the weather has warmed.