Is the 8-8-8 lavender pruning technique the 'foolproof' secret to better blooms?

The 8-8-8 lavender pruning technique has been touted as a 'foolproof' method that will reward you with a fuller plant and better blooms next spring.

There are lots of ways to prune lavender; however, this method is supposed to be one of the easiest ways to remember when and how to cut back lavender. However, it comes with some important caveats and isn't suitable for all plants according to gardening experts.

The 8-8-8 rule means that on the 8th August (the eighth month), you should cut the plant back by about eight inches. 'This is roughly after the lavender has finished flowering for the summer,' explains Julian Palphramand, Head of Plants at British Garden Centres.

'The 8-8-8 lavender pruning technique can be a useful way of remembering how to prune your lavender (if you use imperial measurements!) and encourages the plant to grow fresh, green shoots that will give you plenty of flowers next year,' says Julian Palphramand. It also serves as a handy aide-mémoire that pruning lavender is one of the jobs to do in the garden in August.

Richard Barker, horticultural expert and commercial director of LBS Horticulture, seconds the use of this method for well-established plants, adding that 'cutting back the lavender by roughly eight inches can stop the plant from becoming too leggy or woody, and can encourage it to grow bushier instead. Additionally, cutting back the plant now can promote new growth and give this growth plenty of time to establish before the plant enters dormancy in winter. After its dormancy period is over, the plant will have enough foliage to provide it with the energy needed for the next flowering season.'

'For mature specimens, the 8-8-8 lavender pruning technique will create a neatly clipped shrub that will remain bushy and productive, with lots of flowers next year,' adds Ashley Edwards, head gardener from Crocus.

Vigorous lavender blooms aren't exclusively down to pruning; adding gravel to lavender will also help with growing lavender and promote better flowers next spring.

Does the 8-8-8 rule for pruning lavender work?

Whether you've bought one from a garden centre or mastered how to grow lavender from seed, the experts tend to agree that having a firm date for pruning lavender is not a great idea. Nature doesn't work to a strict calendar, and the right time to prune lavender will vary depending on the weather, temperature and your specific location.

'I have never followed the 8-8-8 rule for pruning lavender,' says Emma O’Neill, Head Gardener at sustainable gardening charity Garden Organic. 'Pruning lavender should typically be done in late August-September, so following the 8-8-8 rule and pruning on the 8th August could potentially be too early.'

Pruning is not the same as deheading, and it is important to know the difference between the two. 'Deadheading (removal of spent flower heads) should be done throughout the summer, but the hard pruning should wait until late August,' explains Emma.

Ashley Edwards, head gardener at Crocus, seconds Emma's cautious approach. 'If you live in a mild area, you may get a second flush of flowers in August, especially if you've already deadheaded earlier in the summer. Wait until these flowers have finished before pruning, as they are a great food source for pollinators.'

Can I use 8-8-8 lavender pruning technique on small plants?

It is also not a good idea to use the 8-8-8 lavender pruning technique on younger plants. Young plants will not have 8 inches of new growth to cut back. This means you'd likely end up cutting into the old, woody parts of the plant.

'We advise not cutting into the old, woody parts of the plant because lavender won’t grow back from those. Make sure to trim where the stems are still green and soft,' says Julian Palphramand, Head of Plants at British Garden Centres.

Does the 8-8-8 rule work for French and Spanish lavenders?

No, you should not use the 8-8-8 lavender pruning technique on French and Spanish lavenders. 'This rule seems to mainly focus on the flowering period of English lavender, so you may need to adjust the times accordingly, depending on the variety of lavender you are growing. Before pruning, you should determine if your lavender has actually reached the end of its blooming period, and if it still appears vibrant, it may be better to leave it alone,' says Richard Barker, horticultural expert and commercial director of LBS Horticulture.

'French and Spanish lavenders can be less hardy and therefore require a more delicate treatment than English lavenders. Always check the type you have and prune accordingly,' says Emma O’Neill, head gardener at Garden Organic.

Pruning essentials

Overall, this is one of those pruning gardening rules that you should take with a pinch of salt. If you have a well-established lavender plant and you're new to gardening, it is a good way to remember to check in on pruning it after it's finished flowering in August. Have you tried this technique?