It is best to prune rosemary in the spring but what are you supposed to do if yours needs to be pruned during the colder months of the year?
Rosemary should not be pruned in the winter unless it grows in an area that never gets frost. Even then, waiting until spring is best since the gradually increasing temperatures and amounts of sunlight over the following several months help it adapt and grow better.
If you want to learn more about this topic, you should stick around and read this article. I go into a lot more detail about pruning rosemary in cold months including when it is fine to do and what you should be aware of. Of course, I also share my recommendation for what you should do instead.
Why You Usually Shouldn’t Prune Rosemary in Cold Months
Even though rosemary can tolerate frost a lot better than many other herbs, it is not indestructible and a very easy way to kill it is to prune it when it is too cold.
You should never prune your rosemary if there is frost. While the plant can generally tolerate frost until about 10-20° F (about -7 to -12° C), foliage that has recently been cut is at higher risk of becoming damaged.
Generally speaking, you can prune your rosemary until 4-6 weeks before the first expected frost. That gives it sufficient time to recover before it gets too cold. When pruning in the spring, you should wait until about 3 weeks after the last frost to reduce the risk of frost damage. Or even better, wait until just after it finishes flowering.
You shouldn’t prune during cold months. Especially in the winter. Pruning in the winter is actually a pretty common mistake. It is far from the only mistake people make when pruning rosemary, though. I have written another article where I cover a lot more mistakes people make when pruning rosemary and how you can avoid them.
Spring to fall is generally the best time to prune rosemary. I go into more detail about that a bit later in this article.
Of course, how much frost your specific rosemary bush can tolerate depends on several factors including its size and growing conditions such as soil type, sunlight, and more. 10-20° F (about -7 to -12° C) is a good general rule of thumb, though. Rosemary usually dies when it gets colder than that.
The exception to all of this is for dead growth. You should remove that right away since it frees up room for healthy growth and reduces the risk of several issues. I have another article where I explain how to remove dead growth from rosemary and why it is so important.
Even though you shouldn’t prune your rosemary in the winter, it doesn’t mean that you can’t use any of it. I explain what I mean below.
Can You Harvest Rosemary During Cold Months? Explained
Never give your rosemary a heavy pruning when there is frost. In fact, avoid heavy pruning entirely in cold months. By cold months, I specifically mean from 4-6 weeks before the first frost in the fall or winter until about 3 weeks after the last frost in the spring.
That said, you can still harvest a bit of rosemary when you need it but be gentle. Let me elaborate.
You can generally harvest rosemary at any time of the year. Even in cold months. Just make sure you only harvest what you actually need at the time and try to stick to a few stems or shoots at the same time. That way, you only do minimal damage to it, which it will recover from easily.
The only exception is if it is colder than 10-20° F (about -7 to -12° C) but rosemary usually won’t survive such low temperatures anyway. If it ever gets that cold or close to it, you can help your plant get through it by covering it with a plant cover to keep it warm, but if the temperatures are this low, do NOT harvest from it.
You can also use a bunch of spruce branches to cover your rosemary in the winter if you happen to have that but you have to use quite a lot. That’s a trick I learned from a very experienced employee at a local garden center who I try to talk to whenever I go there.
Harvesting throughout the year, including during the winter, will cause your plant to become bushier and more productive in the next growing season since the stems you cut will split into two or more. This is one of the primary reasons why pruning is so important. It is not the only reason I recommend doing it, though but you can learn more about that in another article where I specifically cover why pruning rosemary is important.
If you want to harvest a large amount of rosemary at the same time, don’t do it when it is cold. A thorough harvest is not much different from pruning when it comes to how rosemary reacts to it in the winter. Instead, wait until spring before you do that and pick just what you need and not more until then.
Best Time of the Year to Prune Rosemary
The best time of the year to prune rosemary is in the spring after it finishes flowering. It can be pruned from spring until 4-6 weeks before the first frost in the fall or winter, although it shouldn’t be done more than 1-2 times per year.
Most people should only prune their rosemary one time per year, ideally in the spring, but if you live in a very warm climate where it grows rapidly, it is fine to do it twice per year. I have another article where I go into more detail about how often rosemary should be pruned.
The reason why you should prune your rosemary within this interval is that it should have enough time to regrow and for any new foliage to become hardy enough before a potentially cold winter.
You can actually prune rosemary as early as 3 weeks after the last frost in the late winter or spring. This gives it as much time as possible to grow before next winter but it also means that you might interrupt or delay the flowering process.
Delaying the flowering process is fine and might even cause it to grow slightly more than otherwise, but it also means that it might not attract as many bees and other pollinators to your garden.
I have another article that I recommend reading if you want to learn more about why spring is the best time to prune rosemary.
One last thing I want to mention because it is a common misconception is that you don’t have to cut your rosemary back for the winter. Doing so is not necessarily wrong but it is usually not the best option. I have another article where I cover why you generally shouldn’t cut rosemary back for the winter.
If you have decided that it is time to prune your rosemary, I recommend reading my complete guide on pruning rosemary where I share absolutely everything you need to know.