When, Why and How to Prune Lavender

Welcome to Garden Sanity. I'm Laura, and this video covers when, why, and how to prune lavender. First, I'll go over when to prune lavender, what time of year is best, and share a few important reasons why pruning lavender on a regular basis is important. Next, I'll demonstrate exactly how to prune lavender in a few easy steps. And finally, I'll show you an unpruned, overgrown lavender with many large woody stems, which is an excellent, almost extreme example of what regular pruning helps to avoid. Trust me, you'll be amazed at the woodiness of this lavender. It's awful. So when is the best time to prune lavender? You actually have a few options to choose from. One of the best times to prune lavender is late summer or early fall, at least six weeks before the first frost occurs in your area. For me, here in Zone 7 Southern New Jersey, I can still do that now, even though it is the end of September. The flowers are finished blooming, and I can cut these back to get them ready for the winter season. Now some gardeners will do their pruning in mid-summer when harvesting their lavender for drying. If you've already passed the window to prune now in the fall because your first frost is fast approaching, don't fret, because another good time to prune lavender is in the spring, especially if you live in a colder northern area. The steps for spring pruning are quite similar to pruning in the fall, and I'll explain that in a moment. As much as it's tempting to let your lavender grow and get larger, it's more important to give your lavender a good pruning at least once a year. Choose when you want to prune your lavender and mark it on your calendar if you need to. If lavender isn't cut back annually, the stems can grow leggy and flop onto the ground. Leggy stems can also occur if the plant isn't in full sun. Also, if the plant becomes large and overgrown, any of the stems not getting sun, which is usually the lower stems, will become leggy as well. Now why are these leggy stems important? Because leggy stems can develop a woody base, and new lavender growth will not grow out of that wood at all. Let me show you what I mean. Here's a lavender stem with a very woody base. You'll see that indeed there is live growth that has grown out from the wood, but there isn't any fresh growth that will develop on the woody part itself. Now let's look at the greenish gray part of the stems. If I didn't prune any of these stems back as they mature, the green soft stem will become brown and woody. So that's how you get leggy woody stems. Yes, your lavender will still continue to grow and thrive in many cases if it hasn't been pruned back hard over the years, but your lavender just won't look good when it's not in bloom. How do I know? Because this is exactly what happened to my own lavender plants in my front yard garden beds, and stay tuned because I'm going to show you exactly how bad they are right now in terms of being woody. It's pretty amazing, and not in a good way. So the tools needed for pruning your lavender are very simple. You can use hand pruners or garden snips, and if you have many plants you can make quick work by using hedge trimmers, and also use gloves. Now if you have large plants like I do in the front yard, make sure to wear long sleeves to avoid getting scratched as some of the stems can be rather stiff. I'm using this Lavender Phenomenal plant to show you how to prune lavender, and this pruning works no matter which type of lavender you have. As an aside, I love Lavender Phenomenal because it can handle weather extremes better than any other lavender. It handles heat and humidity flawlessly, and it remains evergreen, or ever gray as many gardeners call it, during the winter season. Even when snow gets dumped on it, it doesn't get crushed. So what's the goal with pruning lavender? Well, it's to remove the dead stems and dried flowers, plus some of the living stems, cutting the lavender down to a nice small dome-shaped mound. Pruning in this way reduces the chance of any woody base becoming a problem. So there will be a small woody base at the very bottom of the stems. To see what it looks like if you gently pull the plant apart, you'll see it like I'm showing you here. Now these lavender plants were planted last year, so they're only a couple of years old, and I'm determined not to let them develop woody stems. First, remove the dead stems. It's as simple as grabbing a bunch of dead stems with one hand and just cutting them off the plant, including some of the healthy living green growth underneath the dead stems. You don't have to be super precise with removing the stems, because this is only the first step in cutting your lavender back. Second, examine your lavender plant and determine the shape you want to achieve. Some gardeners will prune them into a dome shape. Think of like a half circle. Others will cut them into more of a rounded shape. It's totally up to you. Personally, I really don't fuss that much with wanting a perfect shape, because plants don't grow in perfect shapes in the wild, so just keep that in mind. So how far should you cut down into the plant? I cut the lavender down, leaving about two or three inches at the most of the green living stems that are above the woody base of those same stems. Now that you cut some of the plant back already, you can get a better look to determine where exactly the woody base ends and the new or current growth begins. Once you find where that is, go up the stem a bit and anywhere from one to three inches, cut above that. As you prune, keep the middle slightly higher than the sides, aiming for that dome shape that I mentioned. The outside perimeter of the plant can be as little as just one inch of green growth above the woody base of the stems. Shape it as best you can, and remember again what I said. Plants don't grow in perfect shapes in the wild, so don't fret too much about pruning these perfect shapes. Now the most important point about pruning lavender is this. Don't be afraid of pruning too much, thinking you might damage the plant. Most people actually do not prune their lavender as hard as they should. As long as you don't cut the plants back into the wood, you'll be fine. And as long as you leave at least an inch of healthy stems, up to two or three inches of healthy stems at the most in the center, your lavender will grow back nicely. Pruning encourages fresh growth, it encourages the roots underground to develop, and the fresh growth will become bushy and full. Depending on the lavender variety, and there are many of them, your lavender may grow large and wide, or it may stay small and compact. Either way, you want to really cut it down hard every fall or every spring. Again, determine when it's best for you. Speaking of spring, if you're pruning in the spring, there's a couple of things to remember. First, prune in early to mid-spring. However, to be sure you're not cutting into dead wood, especially with lavender varieties that are not evergreen for you in the winter, wait to prune until you begin to see new growth on your plants. This way, you'll be able to tell the difference between the healthy part of the stems versus the dead wood, so that you don't cut down into the dead wood by accident. Once you're seeing new growth, do all of the same steps that I showed you for the fall pruning. So, when do I prune? As I showed you, I prune in the fall, but I'm also going to give these plants a good look in the spring too. I may trim them lightly in the spring, not to be overly anal about the pruning, but after seeing how badly my lavender in the front yard became with limited pruning over the years, I don't want to go through that ever again. So for me, a hard pruning in the late summer or early fall, and then a lighter trim in the early spring if needed. That's what I'm going to do. I'll show you that woody lavender in a second, but first I want to mention fertilizer very quickly. Fertilizer is the final step you may want to do. Lavender doesn't need a lot of fertilizer, as it grows best actually in lean soil, not rich soil. However, adding some slow-release organic fertilizer around the perimeter of each plant will nourish the soil over time without any harm to the lavender plants. I use a spoma plant tone for this purpose, but there are several good options available. Okay, time to see some excellent examples of horrible woody lavender plants, and they're growing in my own gardens in the front yard. First, here's a quick look at the pretty knockout roses and the lavender phenomenal in the same bed. So these lavender phenomenal plants were planted in 2014 when we had our landscaping transformed from a green grass front yard to landscaped pavers and garden beds. The three small lavender plants that flanked each side of the front entrance steps grew quite a bit large over time, especially since I wasn't pruning them back hard. I thought I'd let them grow because I loved how they looked getting larger and larger over the years, and then when they began to show a lot of wood, it was too late. All I could do was cut them back each year, but the wood continued to look worse and worse and get bigger and bigger. Here's the one side that I haven't cut back yet, just so you see again what the dried flowers and stems look like still on the plant. And here's the other side, which I pruned a few weeks ago. It's bad, right? Some of this almost looks like odd-shaped topiary plants, but like someone failed at topiary school. That would be me. Besides the wood that developed over time, the plants have really spread out, mainly from the horizontal woody stems, and some of those woody stems actually look like small trunks. So two years ago, I did try an experiment that failed. I planted some new small lavender plants in between these, thinking once they were doing well, I'd just remove all of the old plants. But this didn't work because the large plants and the tall flower stems just kept the new plants in the shade, and those new plants eventually died off. So these plants will come out, and I'd like to start again and do it right this time, just like I'm doing with the lavender in my backyard now. And I'll keep you posted on what I decide to do, if I take them out now or I decide to wait until spring. And I hope that these overgrown plants didn't horrify you too much. It's pretty scary, but I'm keeping it real and showing you my mistakes, which is part of learning how to be a better gardener. So leave any questions in the comments, and until next time, happy gardening!