Late summer is the time to cut back lavender, rosemary and box edges and hedges. Hair cuts all round as the autumn sets in!
Keeping things under control
Lavender, rosemary and box – whether you grow them as edging plants, hedges, topiary or in containers – all need a late summer clip to keep them under control. The rapid growth of spring has slowed and this year’s new growth has hardened off. This, and the opportunity to grow a little before the wet and cold of the winter set in, help minimise any plant damage. Giving your plants a good shape now means that they will look neat over the colder months and be ready when growth starts again next spring.
Remember to use some of those clippings as cuttings!
Lavender needs a severe hair cut
If lavender is not pruned every year it becomes woody and produces fewer leaves and flowers – and less wonderful fragrance as a result.
If you didn’t harvest lavender for drying in June and your lavender has finished flowering, then it’s time to cut it back.
- For ‘English’ lavender (L. angustifolia) such as Hidcote, that’s around mid-August.
- For intermedia lavenders, such as the Grosso I have in my front garden – just under the bedroom window, that’s early September. It’s important to be quite severe with these.
- And for others, such as French lavender and others with ‘ears’ on the flowers, it's when the plants have finished flowering.
And if you did harvest your lavender, it's time to tidy it up if it needs it.
Whichever type of lavender you have, the principles of pruning are the same.
- Use clean and sharp secateurs so that the cut will heal nicely.
- The harder you prune, the more rapidly the plant will regenerate – usually within four weeks.
- When flowering is over, search down at the bottom of the plant for small shoots or nodules and cut back to these. They will grow to about 2cms/1 inch over the next month.
- Don’t cut into woody growth, though, as lavender rarely shoots again. (If a plant is very leggy you can try to make it break lower down: cut it to within a hand’s span of the woody growth and if it does shoot, do it again next year and again until the legginess has gone.)
This Downderry video steps you through different types of lavender and how to prune in late summer.
Finally, in colder and wetter areas, spring pruning might be better. Leaving the old flowers and growth on the plant will protect it through the winter and reduce dieback. Cut back to the first strong bud on each stem in March/April.
Just a trim for Rosemary, please
Rosemary only needs a late summer trim rather than the severe hair cut required by lavender.
- To keep rosemary bushy, clip the plant to look neat.
- If you’re shaping a plant or growing a hedge, you can cut it back by a third.
- Once again, don’t cut into the bare woody part.
Late summer box
August is the time to trim mature box hedges and topiary, and to tidy up younger plants so they stay neat during the winter months. And unlike lavender and rosemary, box will shoot again from bare wood.
Monty Don takes cuttings and gives some guidance about box here.
In good shape in late summer
Gardening is about looking forward and planning as well as enjoying the here and now. As night follows day, so autumn follows summer. Having an autumn garden in good shape is a lovely thing, and cheering when the weather turns nasty. I'm getting the secateurs out.
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