When to cut back lavender to ensure the healthiest plants around

 Stone house with lavender bushes and climbing plants
Stone house with lavender bushes and climbing plants

If you're anything like us, knowing when to cut back lavender has really been more of a guessing game over the years, rather than something rooted in actual horticultural fact. So this year we made it our mission to find out when we should actually be pruning these plants, and how to keep them in tip-top shape.

Of all the garden ideas out there, lavender is one of the most popular herbaceous additions to get started with. It looks and smells gorgeous, likes the UK climate and keeps pollinators like bees happy. And as easy as it is to care for, there are a few bits of knowledge that will keep your lavender healthy and the best it can be.

When should you cut back lavender?

Close up of lavender plants

Pruning lavender is one of the jobs to do in the garden in August into September. 'The best time to prune lavender in the UK is in late summer or early autumn after the plant has finished blooming,' explains Sean Lade, director of Easy Garden Irrigation. 'This allows the plant to recover before winter and encourages fuller growth in the next year.'

'You can also do a light trim in the spring to remove any winter damage, but the main pruning should be in late summer or early autumn.'

When should you prune English lavender?

Close up of bee on lavender flower

Remember that not all lavender plants are the same, so before you get pruning these Mediterranean garden staples make sure you know what variety of lavender it is that you're dealing with. The most popular in the UK are English and French or Spanish.

'English Lavender (Lavandula angustifolia) is the most common type of lavender found in the UK,' says Sean. 'It should be pruned once a year, in late summer or early autumn, after it has finished blooming. You can also give it a light trim in the spring to remove any winter damage.'

When should you prune French lavender?

Exterior of house showing corner bifold doors leading out onto garden with lavender plants

'French or Spanish Lavender (Lavandula stoechas) blooms earlier than English lavender, usually in the spring or early summer,' adds Sean. 'Therefore, you can prune it right after it finishes blooming, typically in mid to late summer.'

How do you cut back lavender?

Stone house with lavender bushes and climbing plants

So now we know when to cut back lavender, but it's also important to know exactly how you should be pruning your plant.

'Use a pair of sharp secateurs for pruning,' advises Sean. 'They provide a clean cut and cause the least damage to the plant. Ensure your tools are clean and sharp to prevent the spreading of disease.'

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'To prune, start by removing any spent flower stems,' continues Sean. 'Next, trim back approximately one-third of the plant's height, focusing on the older, woody sections.'

'Make your cuts just above a leaf node – this is where new growth will sprout. It's important not to cut back into the old, woody part of the plant that doesn't have any green growth. Lavender often struggles to regrow from this old wood.'

'Prune lavender into a mound shape, wider at the base, to allow for even light distribution and airflow. This also helps in shedding water away from the centre of the plant, reducing the chance of rot.'

'Regular pruning not only keeps your lavender plant looking its best, but it also improves air circulation and helps prevent diseases like root rot and fungal infections.'

How do I look after lavender in my garden?

Even if you're a pro at knowing when and how to cut back lavender plants in your garden, there are a few other gardening tips you can do to keep them happy and healthy.

'Lavender plants prefer well-drained soil and lots of sunlight,' explains Sean. 'In less-than-ideal conditions, they may need more care, including possible adjustments to watering and pruning practices.'

'Lavender is a drought-tolerant plant, which means it's more susceptible to problems from overwatering than underwatering. Make sure the soil is dry before watering and avoid getting the foliage wet to prevent fungal diseases.'

'In colder areas, protect your lavender plants in the winter by adding a layer of mulch around the base of the plant, but not touching the plant itself. This helps to insulate the roots without causing stem rot.'