Lavender is often a sentimental plant. After about a decade, it tends to grow old, woody, and overgrown. Learn how to prune it and give it new life.
Pruning woody lavender – key facts
Difficulty – high
Time – 3 years
Success rate – low
Main technique – rotated hard 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
- 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 has trouble growing shoots
Lavender will not grow back from old wood. This basic fact means you can’t simply cut it short, since it won’t grow back.
Cutting back the entire plant all the way to the woody part is too much of a shock for the plant.
Lavender stems specialize in drought resistance
Lavender stems are very specialized.
- To lock water in, lavender stems grow watertight bark without any openings to the outside air.
- It excels at channeling sap and nutrients to and fro between roots and leaves.
- Stems store moisture during dry spells. They release it to leaves when needed.
This drought specialization came at the cost of propagation. Buds on old wood cannot sprout through the bark to turn into leaves and new stems.
Lavender’s resistance to grazing makes growing back unnecessary
Lavender is successfully armed against grazing.
Most animals like deer and rabbits hate eating lavender leaves and stems of the plant.
This is mostly because of the strong-tasting essential lavender oil.
- 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.
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 sometimes a decade old!
- Reducing the shrub in size will channel this power into 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 basic trimming back of lavender after the blooming.
For basic lavender pruning: stay within the “green leaf” area of the shrub.
All the 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 remove half the blooming until the shrub is well formed. Flowers divert energy from new growth (make a lavender wand with the trimmings).
First technique – hard prune your 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 the pruning over several years is what makes it work.
- Discover how to hard prune lavender
In a nutshell, the idea is to remove the longest branches in three or four batches of equal numbers.
- One batch is cut back to the trunk every year
- Other branches are kept for another one or two years.
Second technique – layering
Layering is the fact of burying a portion of a stem under soil. Roots develop within a year. The layered stem can be cut out from the mother plant after one or two years.
Part of the “hard pruning” technique involves keeping stems over a few years, so double your chances by layering them. It won’t interfere with new sprouting from the crown itself, and you’ll have more plants to go around afterwards!
Third technique – the “donut method”
A variation of the layering method is to bury the trunk and main branches of the old lavender plant. This is easy if the center is already bare with long branches falling over to every side.
- Spread the main branches around in a star-shaped pattern. You can layer each one to have additional plants later on. Remove shorter branches that block sunlight to the center.
- In the center, ridge soil up and cover the entire trunk area.
- Use well-draining soil mix that includes gravel or clay pebbles. Cover with mulch.
- When new growth starts sprouting from the center area, success! Start pruning yearly as for a young plant.
- Wait for a whole year before cutting the older, larger branches off (layered ones should be ready after that year). If you cut them off too soon, 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 seeds end of summer.
- Sow end of winter in a layer of soft soil mix.
- Some varieties seed profusely. For example, ‘Munstead’ (an English lavender variety) produces lots of seeds which germinate easily.
- They either don’t produce seeds, or their seeds can’t sprout.
Smart tip about old, woody lavender
Keep pruned woody stems and wrap other herbs around to make a special “Mediterranean bouquet garni” for cooking!
Image credits: Rosalyn & Gaspard Lorthiois, own work