Pruning is not the most complicated task you will have to do when growing rosemary but there are some common mistakes that are easy to make that you should avoid.
In fact, making some of these mistakes can kill your rosemary, so if you want to avoid that, this article is for you.
Lucky for you, I have made all of these mistakes over the years and learned how to avoid them, which is exactly why I wrote this article. To teach you about the mistakes you should avoid (and how to avoid them) when pruning your rosemary.
1. Pruning More Than 1-2 Times per Year
One of the advantages of pruning is that it promotes growth but this is only the case if you don’t do it too often.
Pruning too often will inhibit growth rather than promote it. More specifically, it prevents the plant from ever growing back properly since it doesn’t get the time it needs.
Generally speaking, rosemary should be pruned once per year although twice per year is fine in the warmest parts of the world where it grows rapidly. This gives it enough time to grow back and produce a sufficient amount of new foliage for it to grow larger and become bushier before the next pruning.
This doesn’t mean that you can’t harvest from your rosemary more than 1-2 times per year. It simply means that you shouldn’t give it a heavy pruning more often than that.
You can always harvest from your rosemary but try to only harvest what you actually need.
If you want to harvest a large amount of rosemary at the same time, for example, to preserve it, it is often best to wait for the right time of the year (which I cover next) and do it as part of the annual pruning. That’s what I do and it works great for me.
I have written another article where I go into more detail about how often you should prune rosemary, so you can figure out what to do in your specific situation.
If you aren’t sure if you should prune your rosemary, I have written another article which I recommend reading as I cover several signs rosemary should be pruned.
2. Pruning When There Is Frost
To make sure I shared the best information, I reached out to my father-in-law before writing this article. He is highly educated in horticulture and agriculture and has been working in the fields for over three decades. He has also been growing rosemary for a very long time. This is what he told me.
Plants tend to be more fragile right after being pruned and rosemary is no exception. That’s why you shouldn’t prune it during the coldest months of the year, especially if there is frost.
The best time to prune rosemary is in the spring just after it finishes flowering. That way, it has plenty of time to produce new foliage and become strong before a potentially cold winter.
I have another article where I go into detail about why spring is the best time to prune rosemary, which I recommend reading if you want to learn more.
Of course, the best time depends on where you live although spring after flowering is a great general rule of thumb.
While spring is usually best, you can actually prune rosemary all the way until fall but no later than 4-6 weeks before the first expected frost.
If you live in some of the warmest areas of the world that never experience frost, you can prune rosemary all year round. That said, spring is still best since the plant will be receiving a gradually increasing amount of sunlight over the next several months.
I have written another article, where I go into depth about why you usually (but not always) shouldn’t prune rosemary in the winter including when it is actually fine to do.
Here is a photo of one of my father-in-law’s bushy and healthy-looking rosemary plants which he prunes every spring. As you can see in the photo, he pruned parts of it not that long before I took this photo.
Another common misconception related to this is that you must cut your rosemary back for the winter. This is not true at all, although you can do it in some cases. I have another article where I go in depth with the topic of why you shouldn’t cut rosemary back for the winter.
3. Cutting the Plant Back by More Than a Third
A common mistake when pruning rosemary which can damage it or even cause it to die in severe cases is to cut it back too hard.
A good rule of thumb is to cut it back by about a third. The most important thing is that you don’t cut into the hard and woody parts of your rosemary, because it might not grow back. Instead, make sure you cut where it is still relatively fresh.
As you can see in my photo above, the stems don’t have to be fresh and green. It is fine if they are starting to change color and turn darker, but they shouldn’t be hard and woody.
How much you should cut your rosemary back ultimately depends on your goal. I wrote another article where I went into more detail about how hard rosemary should be pruned to help you figure it out for your specific goal.
Pruning rosemary correctly, which includes not cutting it back by too much, will cause the stems to split into two or more, causing the plant to become much bushier and more productive overall. This is actually one of the primary reasons why it is important to prune it. It is not the only reason, though. I have another article where I cover the topic of why pruning rosemary is important.
4. Using Dirty Tools When Pruning
I have often seen people overlook the importance of keeping your garden tools clean and in good shape. This is not only important for maintaining the tools so you can keep them for a long time but it is also crucial to use clean tools when pruning your plants.
Using dirty pruning shears (or other tools) when cutting your plants significantly increases the risk of introducing diseases.
In severe cases, plants can die from such diseases. This is especially important to keep in mind when pruning since the fresh cuts put it at higher risk.
5. Not Using Sharp Pruning Shears
Sure, you can technically just break the stems with your hands when you are pruning but the risk of damaging the plant is quite high if you do that, so I do NOT recommend it. The same goes for using pruning shears or other tools that are not sharp.
Instead, always use sharp tools for pruning because it makes it much easier to get a clean and straight cut, which significantly reduces the risk of damaging the plant.
If you don’t already have good and sharp pruning shears, I cannot recommend it highly enough. It is so important for so many tasks in the garden. Especially, of course, pruning.
I bought my pruning shears from the photo above a couple of years ago as I am writing this and they still work extremely well. They were even relatively inexpensive. Just make sure you clean them and take care of them.
If you want to learn more about the items you need for this task, take a look at my other article where I cover all the tools and supplies needed for pruning rosemary.
6. Not Removing Yellow, Brown, or Dead Foliage
Foliage that is turning yellow or brown or drying out might be infected with pests or diseases that can spread to other parts of the plant. This can end up damaging the plant or even killing it in severe cases. That’s why you should always prune it away when you see it.
Dying foliage doesn’t necessarily mean that it is infected by pests or diseases, but that isn’t the only reason why you should remove it.
Removing dead or dying foliage allows the plant to spend energy on producing new, healthy foliage rather than trying to keep dying foliage alive.
I have written another article where I cover all the benefits of removing dead foliage from your rosemary and the consequences of not doing it as well as the best way to do it.
7. Pruning the Plant Unevenly
Not everybody cares equally much about the aesthetic aspects of an herb garden, but for those that do (myself included), you should keep in mind how you shape your rosemary bush when you prune it.
You might not want to shape your rosemary in any specific way but you probably still want it to grow somewhat evenly and appear somewhat nice and tidy.
To achieve that, simply make sure you cut the plant evenly all the way around. I like to take a few steps away from the plant and look at it to make sure I cut evenly when I prune mine.
Now that you know everything you should to avoid these mistakes, you can head over to my full guide on how to prune rosemary to learn the best and easiest way to do it while reducing the risk of making these mistakes as much as possible.