While it usually isn’t a problem when rosemary flowers dry out and die, it can sometimes be a sign that something is wrong. I wrote this article to help you determine why it happens so you know if you need to react.
The most common reason rosemary flowers die is their short lifespan. Individual flowers usually don’t last longer than a few weeks at most, however, they are constantly replaced by new flowers throughout the flowering period if the plant is healthy.
If this is the reason why the flowers on your rosemary are dying, you have nothing to worry about. However, it can also happen because of several different problems, so I recommend going through this article to make sure you aren’t missing something that can kill your entire rosemary plant if you don’t take action.
9 Reasons for Flowers on Rosemary Turning Brown and Dry
When I talk to people about why their rosemary flowers dry out and die, it almost always turns out that nothing is wrong and it simply happens as a natural part of the plant’s life cycle, so I want to cover that first. However, I have also seen it happen as a result of some underlying problems that can affect and damage the entire plant if it is not resolved.
With that said, here is my list of likely reasons.
1. Each rosemary flower only lasts for about a few weeks
Most of the time it is not a symptom of a problem when rosemary flowers dry out and die. It simply happens because each flower has a short lifespan of no more than a few weeks at most.
Flowering is part of the process where seeds are produced and mature. Once the seeds are fully developed and matured, the flowers dry out and fall off. Not all flowers end up producing seeds and the ones that don’t do it seem to dry out and fall off faster than the ones that do in my experience.
The production of flowers and seeds is an ongoing process that usually lasts for several months. In tropical and subtropical regions, it can be more or less permanent. Flowers appear and die shortly after but new flowers will continue to appear throughout the entire flowering process. Because of that, you will usually see fresh and dry flowers on the plant simultaneously as in my photo here.
I have another article that I recommend reading if you want to learn more about how long the rosemary flowering process lasts.
The dry flowers will fall off on their own at some point, but if you want to remove them to keep the plant fresh-looking, it is important that you do it right to avoid causing unnecessary damage to the plant. In that case, check out my guide on how to remove rosemary flowers correctly.
2. Insufficient sunlight
Sunlight is one of the key factors that determine how well a rosemary plant grows overall. If the plant doesn’t get the sunlight it needs, everything about how it grows will be affected including flowering. If the flowers are dying, lack of sunlight could be the reason.
Rosemary is native to the Mediterranean region where it naturally receives a lot of direct sunlight. Because of that, it should get at least 8 hours of sunlight per day to thrive. More than 8 hours can help the plant grow even better.
3. The temperature is too low
As I wrote above, rosemary is native to the Mediterranean region where it receives a lot of sunlight. In addition to that, it is also used to high temperatures in the summer, so if it is too cold where you keep it, it can affect the flowers.
In my experience, temperature is usually mostly a problem around the winter, which means that you can’t always do something about it, which is fine. If winter is around the corner (or if it is already winter), the plant is supposed to drop its flowers anyway, so this is usually not a problem.
If you believe that there is a temperature-related problem, you can consider moving the plant to a warmer spot if you keep it in a pot, but if it grows in the ground, I wouldn’t recommend trying to move it. In that case, consider covering it with a plant cover at night to keep it warm.
4. Overwatering
Overwatering is one of the most common problems people run into when growing rosemary in my experience. I have had to deal with it myself multiple times and I have helped several friends and people from my family who also had to deal with it.
Overwatering, as the word indicates, means that a plant has gotten too much water. This can lead to several different problems including dead flowers.
If the problem is severe enough to damage the flowers, it will typically also damage the rest of the plant and be noticeable on the foliage, so look for that. Common signs are wilting and foliage drying out, which will get increasingly worse as the root damage gets worse.
Overwatering leads to root rot, which can be hard to identify. To be certain that overwatering is the issue, you can carefully lift the plant out of its pot like I do in this photo. If the roots look like the ones on my plant in the photo, they are fine. Notice how they look fresh and alive. If they are soft and soggy, they have started to rot because of overwatering. Of course, checking the roots is only possible for potted rosemary. Don’t try to dig up a rosemary plant that grows in the ground.
If your rosemary is overwatered, consider repotting it and giving it a lot of new, dry soil. I have a guide on how to repot rosemary here.
5. Underwatering
While it is not nearly as common as overwatering (at least in my experience), underwatering is another potential problem that can lead to problems with rosemary, including affecting flowering.
Like the rest of the plant, the flowers need water to develop and grow, so if the plant lacks water, it will affect flowering and the flowers.
I should mention that rosemary tolerates drought much better than many other herbs, so while it can certainly happen, I recommend also looking for other potential problems.
If you suspect that your rosemary has been getting too little water, you can carefully lift it out of its pot and take a look at the roots. If they look dark and dry compared to my photo above, underwatering might be the reason. If your rosemary is growing in the ground, don’t try to dig it up to look at the roots.
6. Incorrect soil type
The type of soil a plant grows in plays a huge role in how well the plant grows and while rosemary is a versatile and hardy plant, it is no exception. The wrong soil type can affect flowering and will often result in damaged flowers and foliage.
Rosemary should grow in well-draining, sandy soil without much organic matter. A good rule of thumb to keep in mind is that light-colored soil is usually low in nutrients, so go for some light, sandy soil.
The soil-related problem I have had the most with my rosemary over the years is when I have used soil that is too high in nutrients or has a high content of clay rather than sand. I planted one of the first rosemary plants I ever had in soil with a high content of clay, which means poor drainage, and it died quickly as a result. One of the first things that happened was that its flowers and green foliage started drying out and dying. In this case, it happened because of root damage, which happened because of the wrong soil type.
7. Over-fertilizing
Generally speaking, fertilizer can help plants by boosting their intake of certain beneficial nutrients. While this is often good, it can also become too much and reach a point where the plant becomes over-fertilized.
A common mistake I have seen several times is that people use a nitrogen fertilizer for their rosemary. It can often be beneficial for the development of foliage but it can be at the expense of the flowers.
Too much fertilizer will lead to fertilizer burn, which can be identified by looking at the plant’s foliage. In the case of rosemary, individual leaves will start to look scorched and become brown and dry. This is what you can see in my photo below.
It can affect flowers in a similar way but if you suspect that your rosemary’s flowers are dying because of over-fertilizing, you will also be able to see the green foliage becoming damaged like in the photo.
Rosemary is especially easy to over-fertilize compared to many other plants. I have done a fair bit of experimenting with different fertilizers for rosemary but I have found that the most reliable way to get good results is to use no fertilizer at all for rosemary and only very little if you do.
So far in this article, I have mentioned how it is easy to over-fertilize rosemary and that you should use soil without much organic matter but it can also be too little, which I cover now.
8. Lack of essential nutrients
Lack of essential nutrients, particularly nitrogen, phosphorus, and potassium can lead to poor flower and foliage development.
If this is the issue, you will not only see flowers dying but you won’t see many new flowers developing. If this sounds like the situation you’re in, I recommend reading another article I wrote specifically about why rosemary sometimes isn’t flowering properly because it can happen for other reasons too.
9. Pests and diseases
Pests and diseases can cause a wide variety of problems in plants and even though rosemary is a relatively strong and hardy plant, it is no exception. Some pests and diseases target the roots and some target the foliage and flowers.
Whenever I have had problems with pests and diseases in my rosemary, I have noticed it on the green foliage before anything else. That said, it can also be noticeable on the flowers, but if you suspect that your rosemary flowers are dying because of pests and diseases, I recommend also taking a close look at the foliage as that will almost always be affected too.
Common pests that go after rosemary are aphids, spider mites, spittlebugs, and rosemary beetles. I found a source from the Division of Agriculture and Natural Resources, University of California, where you can see more examples.
Common diseases in rosemary include fungal diseases such as powdery mildew. If you notice a fungal issue on your plants, it is crucial that you isolate the affected plant from other nearby plants or at least cut off the affected parts of the plant. Fungal issues are a common symptom of overwatering.
Learn more about why flowering is important for rosemary
If you want to learn more about why flowering is important for rosemary, what happens to the plant when it is flowering, and what you should do, head over to my complete guide to rosemary flowering where I cover absolutely everything about the topic.