Lavender is often a sentimental plant. After about a decade, it tends to grow large, woody, and unshapely. Learn how to rejuvenate it and give it new life.
Resurrecting old lavender – facts
Difficulty – high
Time – 3 years
Success rate – low
Main technique – rotated severe pruning
Secondary techniques – layering, cuttings, seeds
Dealing with woody lavender is more difficult than for other shrubs. Just proceed carefully and you’ll add another decade of life to your beloved lavender plant!
Woody lavender, not an easy patient
Lavender is different from many other plants that easily root from old wood. While some shrubs can take severe pruning and hatracking, cutting back lavender too hard would kill it.
There are two main ways to rejuvenate old, woody lavender:
- severe pruning one third at a time
- layering stems
A different strategy is to start a new plant from the old one. This can be done through:
- preparing cuttings
- harvesting and growing from seeds
Let’s take a look at each of these techniques! But first, a short overview to explain why lavender doesn’t grow back from old wood… as a result of evolution and adaptation!
Old lavender wood has trouble growing shoots
Lavender will not grow back from old wood. This is a basic fact that makes it difficult to simply cut it short, since it won’t grow back.
- It’s very different from other plants. For instance, you can even sprout winter mimosa from a piece of bark!
Cutting back the entire plant all the way to the woody part is too much of a shock for the plant.
Lavender stems, crucial for drought resistance
The stem of lavender is very specialized.
- It excels at channeling sap and nutrients to and fro between roots and leaves.
- It stores moisture during dry spells and releases it to the leaves when needed, somewhat like the drought-resistant Dracaena marginata.
- To lock water in, lavender stems grow a rather thick bark without any openings to the outside air.
- This drought specialization came at the cost of propagation: buds cannot sprout through the bark to turn into leaves and new stems on old wood.
Grazing resistance at the cost of growing back
Lavender is successfully armed against grazing. Animals like deer and rabbits hate nibbling lavender leaves and stems of the plant. This is mostly because of the essential oils.
- Since it successfully repels biting animals, lavender doesn’t need to grow back from the stump.
Nonetheless, it is possible to coax lavender into sending out new shoots from the base. The key to this is patience and care.
Fountain of youth – racking up the pressure to trigger growth
A grown plant has a strong, established root system. It grew to provide the entire plant with nutrients and water. There’s quite some power in a root system that is over a decade old!
- Reducing the shrub in size will channel this power into the remaining portions.
- There should still be some active branches to ensure circulation.
- Buds and shoots can sprout near the base as long as the plant is still alive.
Techniques to recover an overgrown, woody lavender plant
Whatever the technique you choose to follow, the first step is always to trim the plant back after the blooming.
- Stay within the “green leaf” area of the shrub.
- Here are the steps for basic pruning of lavender
Each of these methods for rejuvenating your lavender will require time.
- Your lavender will look like a work in progress for up to three years. It won’t look nice but it will be fun to see it grow!
- It helps to also remove some of the blooming, as this will divert energy to new growth.
From large to small, hard pruning lavender
Over a few years, typically three or four, you can reduce the size of your lavender shrub.
- This isn’t always successful but it’s always worth a try.
- Pruning all at once would kill the plant.
- Spreading it out over several years is what makes it work.
- Discover how to hard prune lavender
Double your chances with layering
Part of the above step involves chopping off the longest branches in three or four batches. One batch is cut back to the trunk every year, but the other branches are kept for another one or two years.
You can use these “late batches” to make new plants through layering.
A variation of this is to bury the trunk and main branches of the original old lavender plant. This is especially easy if the center is already bare with long branches falling over to every side.
- Use well-draining soil mix, gravel or clay pebbles, and cover with mulch.
- If new growth starts sprouting from the area, success! Clear out old branches that block the sun out and start pruning it yearly as for a young plant.
- Wait for a whole year before cutting the older, larger branches off or you might shock and kill the lavender, even though a small shoot has appeared.
More traditional options, cuttings and seeds
Instead of replacing your lavender with a new, store-bought lavender, you can try to multiply your existing lavender.
Cuttings – this is how professionals propagate lavender.
- You can prepare cuttings from your old lavender.
- Once they’ve grown, you can replace the mother plant with a cutting.
- Spring is the best time to make lavender cuttings.
- There are two ways to take lavender cuttings. Usually, “softwood tips” (green with leaves) are cut and rooted in water or soil mix. You can also take “heel cuttings“, where a young branch is pulled off from a main branch. The trailing sliver of bark is where new roots will form (again in soil or water).
Seeds – Some lavender varieties also go to seed.
- Collect the seeds at the end of summer.
- Sow them at the end of winter in a layer of soft soil mix.
- Some varieties seed profusely. For example, the ‘Munstead’ (an English lavender variety) produces lots of seeds which germinate easily.
Not all lavender varieties produce seeds, though.
- Many of the hybrids are sterile.
- They either don’t produce seeds, or produce seeds that can’t sprout.
- Lavandin varieties are typically sterile.
Smart tip about old, woody lavender
Keep a few of your gnarly, woody stems and use them to wrap other herbs around to make a special “Mediterranean bouquet garni” for cooking!
Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Thick woody lavender by Rosalyn & Gaspard Lorthiois, own work