How to grow rosemary

Rosemary plants are widely sold by gardening retailers all year round, from small plug plants (recently rooted cuttings) up to well-established shrubs in 2 litre pots. Young plants are even sold in most supermarkets.  
 
For the widest choice of varieties, try herb nurseries and larger plant retailers.  
 
Still, you don’t have to buy plants of course – rosemary is very easy to grow from cuttings, so do give it a try. You can propagate from an existing rosemary plant if you have one, or ask friends and neighbours if you can take cuttings from theirs. See our guide to propagating herbs.
 
Seeds are also available from garden centres and seed retailers.

Rosemary can be grown from seed, but germination is often slow and plants will take several years to grow large enough to start harvesting. It’s much quicker and easier to start with bought plants or cuttings (see below).

However, if you do wish to grow from seed, start them off indoors in spring.
 
Thin out the seedlings into individual pots once large enough to handle, then keep in a warm, bright spot and water regularly. They can be planted outside once they’re at least 10cm (4in) tall.

Rosemary is fairly drought tolerant, but new plants should be watered regularly for at least the first summer. Established plants only require watering in long spells of hot dry weather.  
 
Plants in containers need regular watering, especially in summer, as the compost will dry out very quickly.

Apply a thick layer of mulch, such as garden compost or gravel, around the base of rosemary in autumn, to protect the roots from winter cold. If you're using garden compost, leave a gap around the base of the stem to avoid rotting. See our guide to mulching.

Rosemary growing in the ground doesn’t need feeding and should thrive even in poor soil. But rosemary in a container should be given a balanced fertiliser annually after it’s finished flowering.

To keep rosemary compact and encourage fresh young foliage, trim it back lightly every year after the flowers fade, but avoid cutting back into old wood.  
 
Left unpruned, rosemary can quickly become leggy, woody and bare at the base. As they doesn’t generally recover well from heavy pruning, it is often best to replace old straggly plants once they’re past their best. It’s easy to take cuttings (see below) to grow your own replacements.

Rosemary is generally hardy to -10 to 5°C (14 to 23°F), especially older, well-established plants. Still, it’s worth applying a thick mulch in autumn to help insulate the roots – especially around younger plants or in colder locations and frost-prone sites. You can also cover plants with fleece whenever harsh frosts are forecast.
 
Plants in containers are more vulnerable to cold, so ideally move them to a sheltered spot over winter or cover them with fleece. Cold, wet compost can cause rosemary’s roots to rot and die.

Rosemary is easy to grow from semi-ripe cuttings in late summer and heel cuttings in spring. Low-growing stems can also be pegged into the ground to root and form a new plant – see our guide to layering.