Usually lavender plants grow old and woody after 6 to 10 years. Flowers, though still fragrant, grow sparse. And the nice round shape of its youth starts collapsing all over the place! No need to replace it if you go for hard pruning!
Facts about hard pruning lavender
Success rate – rather low
Difficulty – high
Time – 3 to 4 years
Season – Spring
Although not often successful, it’s still possible to rejuvenate your lavender. Hard pruning over several years is one way to succeed.
Hard pruning of lavender – not the usual solution
Most common ways of growing a youthful, round lavender
As shared in our article on rejuvenating old lavender shrubs, lavender only very rarely grows back from old wood.
- Best by far is to regularly trim lavender right from the start.
- An old, overgrown lavender shrub is often simply pulled out and replaced. This is what professionals do in the iconic lavender fields of French Provence.
- It’s also possible to make lavender cuttings or grow lavender from seeds, even those of the original plant!
- Lastly, another technique is to layer the lavender plant.
However, many of us grow attached to the plants we care for. Sometimes they were gifted to us or planted by people we cherish – seeing them reminds us of those loved ones. We’re loathe to just pull it out without even trying!
Severe pruning on lavender, the last chance
Oftentimes, it still is possible to reduce the size of an overgrown lavender plant.
- However, in many cases, the plant won’t survive.
- This isn’t due to any particular mistake or bad luck.
- It’s just that lavender doesn’t cope with hard pruning well.
- Staging the hard pruning over three years (or even four) will make it easier on the plant.
The goal of this technique is to strike a delicate balance. On one hand, hard pruning is necessary to reduce shrub size. On the other, caution dictates that the plant be protected from severe pruning shock.
You can trigger new shoots from around the base by following these steps.
How to hard prune lavender
To maximize success, this hard pruning is spread out over the course of three to four years.
- An initial light pruning is performed on the entire shrub.
- Every year after that, one third of the long, woody branches are cut back to the trunk.
- First perform the regular, basic pruning for lavender.
- This deals with normal growth and shortens the “active tips” of the plant.
- It will help promote branching out.
After that, while still in year 1 of the reforming
- Cut back about one in three stalks all the way back to the trunk. This creates holes in the shrub, which lets light reach the center.
- For each remaining stem, cut back all the way until the first or second pair of green leaves, meaning you cut the tips off but leave one or two pairs of leaves on the bush.
- If winters are harsh in your area, protect your lavender from the cold.
Year 2 – second round of severe pruning
- Normally, a few shoots should emerge from the old base. They grow slowly.
- This being the following year, cut off half of the remaining older, leggy shoots back to the trunk. This is the second “batch” of stems to be cut back totally.
- Trim any new, young shoots to half their new growth. These are your future lavender fronds so you want to make sure they branch out a lot.
Keep pinching or cutting the tips off these shoots every time they reach four or five new pairs of leaves.
Year 3 – wrap up the last woody stems
- Again, more new shoots might emerge, and the previous year’s shoots should have branched out.
- Cut back to the trunk any remaining old, woody stems.
- From then on, simply perform regular lavender trimming procedures every year.
- You should be set for a decade!
How to improve the success rate
Spread the work over four years instead of three
This means you’ll only be removing one in four branches instead of one in three.
- It’s softer on the plant and won’t shock it as much.
Scar old wood to create “young wood” that can grow back!
We’ve seen that one of difficulties is that young branch buds can’t appear on old wood.
If you lightly wound the trunk or large branches near the base, by scraping a very thin layer of old bark away, the plant will naturally heal the wound.
In doing so, it will also produce new buds and branches near that spot.
- Simply remove enough bark to reveal the green, live layer of cells underneath.
- Don’t peel all around the branch, as this would kill it.
- Peel lengthwise from one half to one inch (1 to 3 cm) long. At most 1/4th inch wide (5 mm)
- Make several cuts on different sides and on different sections.
- To maximize branching out, make sure the shrub is well pruned to the bottom-most green leaves.
Layer longer branches
You can also layer lavender.
- Select two or three of the longest branches.
- Fasten them to the ground for them to root.
- Detailed instructions to layer lavender
Layering takes two or three years. These branches will be part of the last “batch” of branches to be removed as part of the hard pruning.
- Doing this not only rejuvenates your lavender plant, it also gives you two or three new plants to grow!
Cuttings, of course
Hard pruning involves cutting pieces off your lavender plant.
- Prepare as many cuttings as you can!
Smart tip about giving your lavender a hard pruning
Make lots of cuttings from the stems and twigs you collect upon pruning. You’ll have the joy of having even more plants to grow and give away!
Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Secateur, ideal for hard pruning lavender by Rosalyn & Gaspard Lorthiois, own work