How and When to Prune Lavender For Beautiful Blooms
Are you looking to properly prune your lavender this season? Pruning lavender isn't complex if you follow the right steps. In this article, gardening expert and former organic lavender farmer Logan Hailey shares seven easy steps for pruning your lavender this season.
Lavender is one of the most adored Mediterranean herbs, but getting it to grow in that quintessential bushy mound is not always a simple task. The elegant purple-topped shrubs you see in English herb gardens are only achieved through regular pruning.
While it may seem like a purely aesthetic task, pruning is actually an essential part of caring for this herbaceous perennial plant. In fact, un-pruned lavender shrubs are more prone to foliar diseases, woodiness, or unsightly leggy growth that can cause the plant to fall over.
Many gardeners are afraid of pruning because they think they’ll hurt or kill their plants. The reality is that most gardeners don’t prune enough.
Lavender actually relishes in this twice-annual haircut because it gives the plant the opportunity to develop its roots and send energy into lush new growth. Most importantly, pruning will ensure you enjoy a dazzling floral display throughout the summer.
Let’s dig into the 7 simple steps to pruning lavender for beautiful and fragrant growth.
First, Should You Even Prune Lavender?
Just like mowing your lawn, pruning encourages a new flush of growth. When you cut back this perennial herb, it triggers the plant to send up more of its gorgeous, aromatic flowers. At the same time, this twice-annual process ensures that your plant stays healthy for years to come.
The benefits of pruning lavender include:
|More Flowers||The most obvious reason to prune lavender is that it encourages better flower production. This is especially important in the spring because cutting back the stems tells the plant to send up new growing tips that will ultimately turn to blooms.|
|Less Disease||The mangled, overcrowded stems of un-pruned lavender can quickly reduce air flow and become a breeding ground for fungal diseases. By cutting back the plant, you can ensure that your lavender stays aerated and doesn’t grow its stems too densely.|
|Healthier Foliage||Bushy, lush foliage growth is both healthy for the plant and attractive to the eye. Pruning triggers more bushy, vibrant lavender growth. On the other hand, un-pruned lavender may grow long, leggy stems that are more sparse and produce fewer blooms.|
|Root Growth||Regular pruning encourages root development in perennial herbs. A strong root system is essential for long-lasting, vigorous lavender plants. It is especially important to prune in the fall because it encourages lavender to store energy in its roots, making it more hardy through the winter.|
|Less Woody Growth||Lavender is technically a semi-woody plant that should only have a small mound of hardwood at its base. Because flowers and leaves don’t grow from old wood, you’ll want to regularly prune lavender to keep it from becoming unshapely.|
|Visually Pleasing Shape||Those perfect gumdrop-shaped lavender mounds can only be achieved through a regular haircut. Lavender naturally can grow quite unwieldy and may not look too great in the garden if it’s left to its own devices.|
Thankfully, pruning is pretty much the only maintenance lavender needs. Once they’re established, these shrubs require very little care aside from an occasional watering or calcium addition.
There’s no denying that pruning can feel intimidating. Where do you start? How much do you cut off? What if you cut off too much? Don’t worry; every gardener has faced these questions at some point. Here’s everything you need to know to get started on a simple twice-annual pruning schedule for beautiful, healthy lavender plants.
Step 1: Use Sharp & Sanitized Tools
Unsanitized tools are one of the main vectors for diseases in the garden. As a rule of thumb, you should sanitize your knives, pruners, or scissors before and after cutting any plant.
This can be as simple as dunking them in a diluted bleach solution (1 part bleach to 9 parts water works well) or wiping the blades with alcohol. Then, rinse off, dry, and get to pruning.
Depending on the age of your lavender, you probably don’t need heavy-duty tools. If you start while the plant is young, you should be primarily pruning soft, green growth for most of its life.
Needle nose pruners or sharp garden shears will easily get the job done. For strategically cutting back woody growth on stems thicker than 2”, a pair of ratcheting pruners or loppers can be really beneficial.
Step 2: Do the First Pruning in Spring
Right after this perennial plant sends out its first blossoms in the spring, it’s time to grab your pruners. This can coincide perfectly with your first harvest of flowering stems for bouquets.
This first cutting is considered a “soft pruning” because you don’t cut it back quite as intensely as you should in the fall. The primary goal of the spring haircut is to encourage another flush of leaves and flowers for the summer.
You should also cut back lavender with this method when transplanting into the ground or a container.
This will help it channel energy into root development in its new home. Whether you’re growing lavender for the first time or starting a pruning regime with an existing plant, remember that spring is the most important time for regenerating the plant to prepare for a vibrant summer.
Step 3: Prune Back ½ of the Green Growth
Wait until the first flush of flowers starts to dry up to begin pruning.
- Start grabbing handfuls of the stem tops and cut them from the base.
- Locate the woody crown of the plant, then go up 2-4” from the base.
- This is where you’ll want to cut.
- Avoid cutting into the hard brown parts of the lower stem.
- It should be easy to cut the green growth with regular hand pruners.
Take your flower stems and bundle them to dry or throw them in the compost. You can also use this opportunity to take softwood cuttings and propagate your lavender into a bunch of new baby plants.
Step 4. Do a Second Pruning in the Fall
After a full summer of flowering, lavender is ready for a “harder” pruning in the fall. If they aren’t harvested, you will notice the last flush of flowers begins to dry and go to seed.
It’s important to get your pruning done at least 5-6 weeks before the first frosts arrive so the plant has time to prepare. In zones 6 through 9, this is typically in the months of September and October.
The main objective of the fall pruning is to encourage the plant to drive its energy downward into the roots. As it puts more nutrients and sugars in the root zone, lavender can build up the robust storage it needs to survive the winter.
This is particularly important in zones 6 and colder because the lavender may be dormant beneath snow for many months.
The hard fall pruning also helps keep the plant stout to the ground so it doesn’t lose branches or collapse in winter storms. Straggly side branches can easily break off under snowpack or high winds.
Cutting them back ensures the best air circulation possible for the muggy, wet, or snowy winter to come. The result is less disease, more cold hardiness, and healthier growth in the spring.
Step 5: Cut Back up to ⅔ of the Plant
The number one mistake gardeners make when pruning lavender is not pruning hard enough. While it may seem like you’re hurting the plant, cutting back up to two-thirds of the lavender’s growth gives it the energy and shape it needs for winter.
- Begin by roughly snipping off any remaining flower stems.
- This will reveal the shape of the plant underneath.
- Locate the center woody crown of the plant.
- Depending on the lavender’s age, it may look like a stout trunk with several side branches or a thin woody twig that is still developing.
- Either way, use this crown as your focal point throughout the pruning process.
- Start cutting the soft green stems about 1-2” above the woody crown.
- It should be easy to snip them and lay the stems to the side.
- It will look like one-half to two-thirds of the plant’s overall height has been removed.
- About 1-3” of silvery-green growth should be left behind at the base of the plant.
When in doubt, I recommend pruning harder than you think you should. As long as you don’t damage the crown, you won’t hurt the plant.
Step 6: Shape to Fit Your Desired Needs
Some gardeners prefer a gumdrop shape, a stout mound, or even a conical shape for potted lavender plants. As you make your cuts, you may go shorter on the sides and longer in the middle to create an arc or mounded shape. This will ultimately affect how the plant grows throughout the following year.
Imagine a circle around the perimeter of the crown and a mound over the top.
This 3D visualization will help you shape the plant as you cut. Regularly step back and examine the plant from ground level and above to ensure you are cutting into the shape you want. Imagine how each of those stems will send up a new flower stalk in the spring.
If this is the first time pruning your lavender after a year or more of growth, it may take a few seasons to achieve the ideal shape you want. If you have neglected pruning your lavender, you will have to be even more patient about getting it back to an aesthetically-pleasing shape.
Step 7: Avoid Cutting Into the Wood Crown
The most important thing to remember during the pruning process is to avoid cutting into crown wood. Though it doesn’t have any golden jewels around it, this base crown is like the heart of the lavender plant. It mediates the growth between the below-ground and above-ground plant parts, essentially acting like a bridge between the roots and stems.
Just like a strawberry crown or a daffodil tuber, lavender’s crown needs to stay slightly above the soil in order to resist root rot. Injury to the crown can easily introduce pathogens. Cutting off too much of the heartwood can damage or even kill your lavender.
While “don’t cut into lavender wood” seems like a hard-and-fast rule, some rules are meant to be slightly broken. Expert lavender growers assert that cutting into the wood can be justified when the plant has many branches that pose a risk to its health.
For example, if you haven’t pruned your lavender in a while, it may have long unruly branches growing out to the side that may snap off under pressure. It is OK to strategically cut these back.
Imagine the lavender crown as a tree trunk: chopping off a few side branches won’t hurt it, but slashing a saw through the center could kill the tree. Use your best judgment to ensure that the plant has enough of its crown healthy and intact to sustain its growth through winter and the following spring.
Pruning is vital for healthy and beautiful lavender growth. Thankfully, it doesn’t have to be rocket science. If you feel intimidated by pruning, rest assured that bad pruning is still better than no pruning at all. These plants are quite resilient and forgiving.
The most important tips to remember about pruning lavender are:
- Always sanitize your tools.
- Cut back about half of the lavender’s green growth in the spring.
- The goal of the spring pruning is encouraging new flushes of growth and flowers.
- Do your second pruning in the fall when the last flush of flowers has faded.
- Use this time to shape the plant into an aesthetically-pleasing form.
- The goal of the fall pruning is root development.
- The spring pruning is “softer” because it leaves 2-4” of growth above the base.
- The fall pruning is “harder” because only 1-3” of stems are left behind.
At the end of the day, pruning is just like giving lavender a haircut. You can even teach kids how to do it!