One of the most important things when pruning rosemary is that you don’t cut it back by too much or too little as that won’t lead to the desired result. How much you need to cut your rosemary back when pruning depends on your goal but here is a good general rule of thumb.
As a general rule, rosemary should be cut back by about a third when giving it a hard, annual pruning. Light pruning or harvesting where stems are only cut back by a few inches can be done multiple times throughout the year as long as the plant has enough time to grow back before the next pruning.
While this is a good general rule to remember, how much you should cut your rosemary back ultimately depends on your goals with the plant, which is exactly why I wrote this article.
In this article, I cover how much you should cut your rosemary back no matter which situation you are in, whether you want to give your plant a hard pruning, or a light pruning, remove dead growth, shape the plant, or something else.
So let’s get into it.
How Much to Cut Back Rosemary for an Annual Hard Pruning
Once a year, typically in the spring, it is a good idea to give your rosemary a hard and extensive pruning. This is done for multiple reasons including to prevent the plant from becoming too woody and leggy and to reduce the risk of several problems, but the primary benefit of a hard, annual pruning is to encourage new growth.
This annual pruning can also be seen as a “renewal pruning” since you cut back quite a bit.
When doing a hard annual pruning of your rosemary, you can safely cut the entire plant back by one-third.
You can take each stem and cut them back by a third but in my experience, you can save a lot of time by grabbing a handful of stems and cutting them all at the same time. Just make sure you don’t cut them back by more than a third.
If you, like me, enjoy using rosemary when cooking, I recommend saving the leaves and fresh stems you remove when giving it the annual pruning. I usually let them dry out fully and chop them into small pieces which I save and store in a dry, dark place.
In the vast majority of the world, rosemary should only be pruned to this extent once per year, but there are some places where it can actually be beneficial to do it twice. If you want to learn more about this, head over to my article about how often rosemary should be pruned.
When giving your rosemary an extensive pruning, I recommend also removing any dead or dying foliage. I explain the best way to do this a bit later in this article.
How Much to Cut Back Rosemary for Light Pruning or Harvesting
You can give your rosemary light prunings multiple times throughout the year and depending on its size, you can usually also harvest a bit whenever you need it without having to limit yourself too much.
When you harvest from your rosemary or prune it lightly, it is important that you don’t cut it back too much as it will take too long for it to grow back.
Cut stems back by 1-2 inches when you harvest from your rosemary or give it a light pruning. Avoid cutting it back by more than that to reduce the time needed for the plant to regrow and to ensure that you harvest the freshest foliage.
As long as you don’t cut more than a few inches from each stem, you can actually do it more or less all year round. If you prune harder than that, you should avoid doing it in the late fall, winter, or early spring. I go into more detail about this in another article where I cover the topic of pruning rosemary in cold months.
If you give your rosemary a light pruning or harvest multiple times throughout the year, make sure you allow it to grow back before you do it the next time. I usually harvest from a different part of the plant every time I harvest. That way, I only take what I need while still cutting the plant back evenly over time.
How Much to Cut Back Rosemary When Removing Dead Growth
It is not at all uncommon to see dead foliage on rosemary and usually not a cause for concern although it can be. Regardless of why it happens, you should prune away any dead growth from your rosemary when you notice it.
It is important that you know how much of the dead growth to remove, though, as it might not have the desired effect otherwise or can even do more damage than good.
When removing dead growth from rosemary, cut about half an inch (or about 1 cm) into the fresh foliage so that any dead growth is removed entirely.
I have tried to illustrate this with the photo above. As you can see, one of the stems on my rosemary plant in that photo is beginning to turn brown and dry out, so I cut into the fresh part of the stem just below the part that is drying out.
You might experience that entire stems are turning yellow or brown and drying out. In that case, remove the affected stems entirely.
Removing dead growth is important since it reduces the risk of fungal diseases and other problems and encourages the plant to produce new growth rather than spend energy on recovery. I have another article where I cover the topic of removing dead growth from rosemary including, of course, the best way to do it and why it is important.
How Much to Cut Back Rosemary When Shaping the Plant
Rosemary can become quite dense and bushy if pruned and cared for properly which makes it ideal for shaping.
When shaping rosemary, be careful not to prune it too aggressively since cutting it back too much can prevent it from growing back properly (or at all) and since you can’t undo it.
My best advice is to cut little by little and not more than a few inches per cut. Remember that you can always cut away more but you can’t undo it if you cut too much.
Trim back any excessively long or unruly stems to maintain a compact, rounded (or whatever you prefer) shape. Do not cut your rosemary back by more than a third in total as it might not grow back properly.
Depending on how you want to shape your rosemary, different tools might be necessary. That’s why I wrote another article where I cover all the tools and supplies needed for pruning rosemary and explain when each is needed.
What Happens if You Don’t Cut Rosemary Back?
Rosemary can grow and thrive without ever being pruned but chances are you want to do it anyway. Keep reading to learn what happens if you don’t.
If rosemary is never pruned, it will become leggy and scraggly and the base will become hard and woody within a few years.
Rosemary grows naturally in many parts of the world where nobody comes to prune it and while it can thrive regardless, it won’t become nearly as productive as if it is pruned.
The photo above is from Spain where rosemary grows naturally and as you can see, the rosemary bush in the photo is much thinner and much more scraggly than if it was pruned every year like you normally would when growing it at home.
What Happens if You Cut Rosemary Back Too Much?
If you cut your rosemary back by too much, it can negatively affect its health and appearance.
Rosemary is sensitive to heavy pruning and should not be cut back by more than a third since it usually doesn’t grow back from hard, woody growth.
Cutting rosemary back by more than a third can lead to stunted growth due to stress and shock. The plant will usually recover slowly but in severe cases, it might never fully recover.
I should mention that some rosemary varieties can tolerate heavier pruning than others. For example, the prostrate rosemary varieties (also often called creeping rosemary) can usually tolerate heavier pruning than the more common upright-growing varieties.
As you can see, incorrect pruning can lead to problems. That’s why I wrote a full guide on how to prune rosemary with all the information you need so you can avoid these problems.