When to prune rosemary - to keep it thriving for your next Sunday roast

If you grow rosemary in your garden on your window sill you will already know how powerful and punchy little super herb it is. 

The drought-tolerant plant, Salvia rosmarius, originally comes from the Meditteranean and is an evergreen shrub that grows small and delicate silvery green leaves. If left to flower rosemary blooms pretty and petite blue flowers. 

Not only is rosemary aromatic and fragrant added to roast lamb and poultry, crunchy roast potatoes, stews and soups. The hero herb is antioxidant-packed and full of anti-inflammatory compounds to boost health and well-being. 

Knowing how to propagate and grow rosemary is a budget-friendly herb garden idea that will reward you and your home greatly and is super easy to achieve.

'Rosemary can grow quite well in the UK climate, although it does need extra shelter during the winter. The rosemary plant requires full sunspots outside, well-drained soil, and shelter from wind. It can tolerate temperatures down to -6°C,' says the Director of Polhill Garden Centre, Josh Novell.

When to prune rosemary

Knowing when to prune rosemary is one of the crucial points of how to grow rosemary properly and will avoid herb garden mistakes and ensure your shrub remains healthy. Being a perennial plant, pruning rosemary will continue to provide you with a delicious crop, if planned and executed correctly. 

It's important not to get rosemary pruning confused with rosemary harvesting. The Royal Horticultural Society (RHS) states that Rosemary is evergreen, so can be harvested all year round, but the soft new growth in summer has the best flavour. Snip off any shoots as required, aiming to keep an attractive shape to the plant.

Pruning rosemary is necessary to ensure the popular garden herb keeps its shape, delay stems from turning spindly or woody and continues to produce a healthy harvest. 

The best time to prune rosemary is during late spring. This gives new growth time to establish itself before winter returns.

'Rosemary is one of the most reliable Mediterranean plants we can also grow in the UK. Prune Rosemary when the spring growth has shot up to keep it in shape. Keep some of the cuttings to grow new plants. Free plants are one of the great benefits of learning when to prune,' explains sustainable gardener, Melanie Hick.

Wait until the plants have finished flowering for best results.

How to prune rosemary

What you'll need

• Established growing rosemary
• Rubbing alcohol
• Sharp secateurs 
• Gardening cloves
• A container to collect clippings

Once you know when to prune rosemary and that time of year arrives, start by preparing your tools.

'Prune shears or small sharp scissors are best for pruning rosemary, as they provide control and precision. Make sure that your tools are sterilised with rubbing alcohol before use, especially if you’ve used them recently on other plants,' advises Josh Novell.

'Make sure the shears haven’t gone blunt when tackling the thicker branches. The sharper the better when handling stubborn stems. Always remember to wear suitable garden gloves to ensure you’re protected from any potential injuries,' agrees Chris Bonnett at GardeningExpress.co.uk.

Next, check the shrub for dead or damaged branches. 

'Prune away any dead or damaged branches with your pruning shears. Be sure to remove all of the brown parts, as these could encourage disease in the plant. Deadhead spent or faded flowers damaged or diseased shoots, and low-lying branches that touch the ground. Cut back to the first set of green leaves or to a main stem,' says Josh Novell.

'Cut away any overgrown growth that has become too dense and is blocking airflow around the plant. It’s important to keep the overall shape of the shrub in mind when pruning, as over-pruning can result in a less attractive-looking rosemary plant.' Continues Josh.

Like Rosemary's Mediterranean cousin lavender, avoid cutting back stems too close to the wood as the plant will never recover and you will need to buy a new shrub or propagate a fresh batch. 

'If you want to make your rosemary plant look fuller, reduce the cutting to around one and a half inches so the branches start the splitting process and create a thicker appearance,' adds Chris Bonnett.

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