Hard Pruning Lavender

Lavenders benefit from annual pruning immediately after flowering to help them remain compact, dense and shapely. If you prefer to let them run riot, au naturel, they will become sprawling and woody and can sometimes take on a beautiful gnarled character but then it will be too late to change your mind as they cannot regenerate when pruned back into thick old wood. Learning just how far you can cut back lavender and have it rejuvenate is a matter of trial and error, but younger plants can definitely be cut back harder than older ones.

To test the limits, after my lavender finished flowering this August, I decided to do an experiment and prune them back much harder than usual. I had read an article saying that most people assume lavender cannot regenerate from old wood, so only give their shrubs a light pruning. Harder pruning, they explained, was not only possible, but desirable, as it would lead to more compact, dense and robust plants. So I decided to give it a go. Here is what happened…

July

The photo at the top of this post shows my white English Lavender flowering it’s heart out in the middle of July. The last flowers go over in the third week of August, when I usually take the secateurs to them and cut back into green wood, not too far, leaving the clumps like this…

Mid to Late August

They soon recover, but with such a light prune the plants increase in width by about 4 inches per year. If I carried on like this they would soon outgrow their space. In the past I had assumed that they would not tolerate heavier pruning so I had lived with this gradual bloat, but they are now approaching the limit of their space and I need to keep them under control, or remove them altogether. This set me wondering: have been over-cautious? Perhaps they can take a heavier pruning than I have given them credit for.

There is a clue, if you look closely at the stems, you can see how far back the buds go. If you cut back harder, these lower, smaller buds should grow away fine. But would there be enough to create a dense new mound of foliage? Only one way to find out…

After looking carefully for these tiny lower buds I took the secateurs to the lavenders for a second time, taking off another 2 to 3 inches of older wood. It was a bit disconcerting to see the first shrub I attacked left with almost no leaves!

One lavender heavily pruned… three more to go…

The lavender in the background has only had the first light prune. The one in the foreground has had the second, much harder pruning. After completing the pruning of all four of my lavenders I mulched and watered them to help them recover.

The Results

Two Weeks

Two weeks later in late August… The tiny buds are beginning to break. There don’t seem to be many on each stem. Did I cut back too far?

Two Months

The plants are now covered in new foliage which seems to have broader leaves than usual. Although some of the heavily-pruned stems have died back and have no new shoots, there is new growth emerging deep down in the centre of the shrub coming from close to the base which I did not expect. I now think I should have been brutal with these plants from the start.

Immediately after heavy pruning vs 2 months later

A close look reveals lots of new growth coming from the base and centre of the plants. I now wonder whether I could have cut back even harder in August, especially as these are relatively young plants. The dead stems that have not produced shoots now look unsightly and could, no doubt, be pruned out, but I will leave them until spring to help protect the new growth from the frost.

Here are the other two lavenders which are beginning to fill out reasonably well. I wonder what they will look like by the spring? Hopefully dense rounded mounds, in keeping with the other shrubs in this bed. We will have to wait and see.

[I’ll post further updates below as time goes by]

[Edit: May 2020]

The following spring

9 month’s after hard pruning

As you can see the lavenders have not only recovered from their heavy pruning, but have come back fully, producing a dense bun of foliage with plenty of flower spikes.


2 thoughts on “Hard Pruning Lavender”

  1. Thanks for an informative post on lavender pruning. I have a very old/ very large lavender bush which has done well over a few years with a hard prune but the main wood stems of the bush are now very large and old and I worry prone to snapping in heavy winds. Is there a certain point when a large lavender bush would need to be removed and a new one planted when the base stems are so large?

    Reply
    • Lavenders are considered short-lived shrubs and are generally replaced every 5 to 10 years. I knew a couple of 20+ year old ones outside a rectory which had developed beautiful gnarled stems, twisted and charming. I guess it’s a matter of taste when exactly you replace them, or you could let fate (the wind) decide for you.

      Reply

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