Known for its deliciously fragrant purple flower spikes, lavender is a famous perennial herb that performs best when cut back once or twice per year. This Mediterranean native usually grows as a semi-woody herbaceous plant, which means that it retains a woody crown but regrows its softer green tissues every season during spring and summer flowering.
If you want to encourage more flowers and an attractive shape, proper pruning is crucial. This also keeps the plant healthy by reducing diseases and preventing winter damage. So, when and how should you cut back your lavender? This quick guide has everything you need to know.
When Should You Prune Lavender?
The best times to prune lavender are in the spring and fall. Cut the shrub after flowering in the spring, removing up to one-half of the green new growth. This will encourage a second flush of blooms. There is no need to worry about shaping the shrub until the fall after the last flowers have faded.
Fall pruning is the time to prune off up to two-thirds of the plant. Surprisingly, most gardeners fail to prune their plants hard enough. “Hard” pruning means cutting back to just 2-3” of silvery-green growth at the base. This also allows you to shape the shrub into a gumdrop or other form. As long as you don’t stab or damage the woody crown, it is safe (and highly recommended) to prune heavily in the fall because it promotes stronger, more lush growth next season. It also ensures a gorgeous clump of fragrant floral spikes with long stems for harvesting.
How to Cut Back Lavender
Like any pruning activity, the most important thing to remember is to make clean cuts. Sharp, sanitized tools are essential so the herbaceous stems don’t get shredded or damaged. Also, take care not to cut into the woody central crown of the herb, as this can cause permanent damage.
Clean and Sanitize Your Tools
Ergonomic hand pruners are the best tools for this occasion. If you have extremely large or overgrown shrubs that need to be reclaimed, loppers may be necessary. Use a sharpening stone to ensure the blades are as sharp as possible.
Before you begin, remember to sterilize the blades. Sanitizing your tools can be as simple as swabbing with alcohol or spraying with a bleach solution (1 part bleach to 9 parts water). This is a useful practice for any pruning activity, especially when moving between plants that have succumbed to disease. Pathogens easily travel on blades and can enter plants through wounds.
Prevent this by keeping your sanitation spray with you and properly disposing of infected clippings.
Harvest First Flowers
It’s easy to do the first round of lavender pruning because it usually coincides with the first flower harvest of late spring. The aromatic purple spikes emerge on long, slender green stems. Depending on your use, you may want to harvest lavender when one-third to one-half of the buds have opened. Catching the buds before they fully open ensures the highest essential oil content.
Grab handfuls of flowering stems and cut as close to the base as possible to ensure long, elegant stems. Most varieties of this famous herb bloom twice or continuously throughout the season. The autumn flush is often larger and more abundant than the first spring blooms. Rest assured that your spring cuttings will promote an even greater fall show!
If you live in an area with a short growing season, you may only get one major harvest, but you can still plan for a second fall pruning.
Prune Half of Green Growth
Generally, spring harvests include pruning back about half of the green growth. You never want to jab into the woody core of the plant. Instead, make easy cuts on pliable, green stems. If there are excess leaves, you can prune those back as well to ensure a big second flush of blooms.
Prune Again in Fall
Late autumn is the time to “hard prune” your herbaceous shrubs. You don’t want to do this too early or too late. About 5-6 weeks before your first frost date is ideal. For zones 6 through 9, this is usually in September or October.
If you prune too early, it can inadvertently cause premature regrowth and flowering that may take on damage in the winter, but if you cut too late, the plant may not have sufficient time to funnel its energy into the roots to prepare for winter.
Remember that herbaceous shrubs die back most of their foliage and go dormant underneath the surface. In zones 6 and colder, hard pruning makes it easier for the plant to gather its resources because its stature is more stout and bare branches are less likely to break off in winter storms.
Remove Up to Two-Thirds
Don’t be afraid to cut back more of your lavender plant than you think you need to! Fall pruning is the time to remove up to two-thirds of this year’s growth. This enhances air circulation and ensures bigger bursts of blooms next year.
First, use your pruners to snip off any remaining flower stems. Next, locate the central woody crown or trunk. Young plants may only have a woody twig, but it is vital to keep this crown in mind so you don’t cut into it. It should be fairly easy to move pruners through the pliable soft stems. If the wood feels too hard to cut, don’t! The plant needs to retain its woody growth.
Shape as Desired
As you snip the green stems, watch the shrub’s shape slowly shrink. There should only be about 1-2” of pliable stems left above the crown. The plant may look like a stubby or spiky mound, but this is actually perfect for overwintering. Only a few inches of greenish-silver growth should be left at the ground level.
If you want to re-shape the herb as a hedge or a gumdrop, this is the time to do it! You may cut a little closer on the edges and leave more stem on the top. Shaping creates a rounded, tidy appearance. Some gardeners even prune topiaries in elaborate shapes! Don’t be afraid to get artistic.
Do Not Cut the Crown!
Like its cousin, rosemary, lavender is a semi-woody herbaceous perennial. It doesn’t form a strong woody trunk like a tree, but it still has essential woody growth that persists through the winter. The rest of the green herbaceous “softwood” can be removed. As long as you don’t cut into the crown, your lavender will remain healthy and happy for next season!
The woody crown is the most important center of the plant. Much like a daffodil tuber or strawberry crown, this wood ensures proper regrowth, bridging the gap between dormant above ground parts and the nutrient storage in below ground roots. Think of it as the heartwood. Damaging the crown could result in weakened growth, disease, or even death. If it feels very difficult to make a cut with pruners, it is probably because you’re cutting too close to the wood.
Key Takeaways
It’s best to cut back lavender once in the spring and again in the fall. The spring haircut is less intense, removing just one-third of the green growth after the first flush of flowers. This can coincide with floral harvest. The second haircut is more harsh, cutting back to just a few inches of silvery-green stems sticking up above the crown level. Use this session to shape and train the plant.
Don’t be afraid to cut back hard—it can actually promote stronger growth and blooming next season. As long as you don’t damage the woody crown, your herbs will return healthier than ever!
