Lavender is a popular plant that finds its way into many a home garden. Perhaps it’s for the heady fragrance or to have a flush of purple reminiscent of the fields of Provence in the garden or to pick for your own culinary or DIY projects. It’s a great-drought tolerant pick and works well in landscape borders. However as they mature, lavender plants will spread and can begin to look a little bedraggled. Pruning the plant can help to contain it in the garden and keep it looking neat. Knowing when to cut back lavender is important.
I’ve had lavender in the gardens of both my homes and I’ve learned a few maintenance lessons along the way. For the purpose of this article, I’m going to focus on lavender plants that are hardy in lower growing zones, like English lavenders (Lavandula angustifolia). Varieties like ‘Hidcote’ can withstand winter temperatures down to about -20°F (-28°C). Where I live, French lavenders and Spanish lavenders are grown as annuals.
Why prune a lavender plant?
Pruning your lavender plant removes the spent flower stalks, if the flowers weren’t harvested the previous year. It also keeps the plant more contained in the garden. And it helps it to maintain a more uniform shape.
While your plant may be a nice, compact mound for the first few years, over time, lavender can become a bit gnarled and scruffy looking. Even despite your best pruning efforts, lavender generally has a lifespan of about 10 to 15 years.
Keep in mind that if a plant is looking scraggly and there is still some green growth coming from the outer edges of the plant, close to the ground, you can create new lavender plants through a process called layering. This is a type of plant propagation where a new plant is created while still attached to the original plant. If you propagate new lavender plants from an old one, you’ll be able to discard the mother plant once it’s past its prime. This also means you don’t have to purchase more lavender plants, which will save you money! Details on how to do this are further on in the article.
Why is timing important in determining when to cut back lavender?
It’s easy to assume that lavenders are like other herbaceous or woody plants that you can prune right back to the ground while the plant is still dormant. And indeed the base of lavender as it ages becomes quite woody looking. However this is not the case. Lavender is actually classified as a subshrub. This type of plant has stems that are woody, except for the new growth that appears and dies back in winter. Characteristics include a low growth habit with these stems being close to the ground.
Even though lavender has the characteristics of both woody and herbaceous plants, the former traits mentioned above (low growing with ground-hugging growth) mean they are more prone to winter damage. They also do not enter true dormancy, they are merely “resting” in the winter. Other examples of subshrubs include Russian sage and thyme.
How do you know when to cut back lavender?
In the early spring, lavender plants look pretty dead until they start to sprout fresh growth. You don’t want to inadvertently cut back a healthy plant. With hardy lavender, it’s a good idea to wait until there is some green growth coming in, so you can see where to make your cuts.
It’s also prudent to wait because trimming in late winter (or even the previous fall) can prompt new growth, leaving the plant highly susceptible to frost damage.
Pruning back lavender stems
There are a couple of times a year that you can prune lavender plants: in early spring and after the plant has bloomed. In early spring, wait to do any trimming until you see signs of leaf growth. At this point you can don a pair of gardening gloves and prune off spent woody stems if you didn’t do this previous year. Hedge shears can finish this task off pretty quickly. Cut stems back to where the leaf growth starts.
Hand pruners make it easy to get into the dead parts of the plant and snipping away the dead wood. (Dead wood will break easily when you gently bend it.) Be careful with your cuts as you don’t want to expose any fresh growth at this point in the season that could succumb to spring’s extremes. And you also don’t want to sacrifice any blooms by prematurely snipping them away. Snipped stems can be fished out of the plant and tossed in the compost.
How to cut back lavender
When the lavender flowers start to fade after blooming (usually around late spring or early summer), you can deadhead the flower spikes with hedge shears. This is also the best time to shape your plant. You can be more thorough with your pruning at this point because all threat of frost has passed. You still can’t raze your plant to the ground and hope it will come back with vigor. You need to be a bit judicious with your cuts. You can cut back about a third of the new growth to shape your plant. Make sure you can still see a few leaf nodes in a stem. Always avoid cutting the woody part of the plant unless there is a piece that is obviously dead.
When you purchase a lavender plant and plant it, it’s fairly compact and usually perfectly shaped. It will stay like that for the first couple of years. Gradually the plant will spread outwards. As the plant really matures, it may throw out these little chunks of plant that are attached, but look almost like a separate plant entirely.
In the spring, at the same time as you are pruning back the dead wood, you can isolate these pieces and propagate more lavender through a technique called layering.
To do this, gently scratch some of the bark away from the woody piece that’s touching the ground near the root. This will expose some of the new growth, which will be green under the bark. Lay the piece of plant back upon the soil, gently pressing it downwards. You could weigh it down a little by gently placing a rock on the stem, being careful not to break it.
If and when roots form on this piece of the plant, you can separate it from the mother plant and move it to a different part of the garden.
Find more pruning tips for perennials and shrubs