The Rhododendron is one of the most beautiful flowering plants in the world. It is also incredibly common, considering the fact that it’s so easy to grow and doesn’t require a lot of effort to care for either.
It is a genus of more than 1,024 woody plants that are found primarily in parts of Asia. However, you should know that the plant is quite widespread in its reach, and can be found in the Pacific Northwest as well.
It is also the national flower of Nepal, and the brightly colored flowers produced by the plant usually bloom all the way from the late winter until the first few weeks of summer.
Needless to say, the plant is a mainstay in most gardens, mainly because it adds a touch of color and makes the place look incredibly pretty. If you plant different kinds of rhododendrons in your garden, you will be treated to an array of multicolored blooms for almost half a year!
But, despite the fact that it’s pretty easy to grow and doesn’t require a lot of effort, you should know that with the passage of time, the leaves of your rhododendron plant might begin to turn brown or yellow. This usually happens due to a number of reasons, primarily when the conditions required by the plant are not met.
When that happens, you might want to take a close look at the plant to figure out what’s causing the problem. This plant is a bit sensitive, so you will need to take action quickly and fix the problem, otherwise the health of the plant might be affected, and the quality of blooms will suffer too.
So, without further ado, let’s talk about a few reasons why the rhododendron leaves might turn brown or yellow.
1 – Nutrient Deficiency
One of the most common reasons why your plant might suffer is when it is lacking in nutrients. These nutrients are required by the plant to thrive and to maintain the quality blooms.
When you notice the leaves turning yellow and the veins becoming apparent on the leaves, it is a pretty clear sign that your plant is suffering from a lack of nutrients.
It also indicates that the pH value in the soil has decreased considerably. You must understand that this plant loves acidic soil, and when the pH value drops too much and the soil turns alkaline, they are going to start exhibiting signs of a nutrient deficiency, most notably iron.
This is what causes the green pigmentation of the leaves to break down, and also causes the plant to turn yellow.
2 – Powdery Mildew
Another common problem that can cause the leaves to turn brown or yellow is powdery mildew.
This is a very intrusive fungus that will cause the leaves to turn yellow, especially the extended ones. This is a powdery fungus, usually white in color, which tends to grow on the yellowing part of the leaves.
Your plants are going to be most susceptible to powdery mildew during the spring and the fall season. The nights turn cooler and the days become warmer, which provides the perfect atmosphere for the fungus to spread.
You should know that the leaves that are affected by the fungus will also begin to curl up inward and then drop off on their own. You will also notice a distortion in the flowers.
Again, you don’t need to worry about your plant dying because of this fungus; but the blooms are going to be affected. You might want to take action and get rid of the mildew as quickly as possible before it spreads to other parts of the plant.
3 – Phytophthora
Another disease that could cause discoloration such as brown or yellow on the leaves of the rhododendron is phytophthora.
The plant will start exhibiting clear symptoms as the leaves will begin to wilt and the health of the plant will suffer drastically. You should know that this is a serious problem because your entire plant might eventually die.
The stems of the plant might also sustain some damage, and you might notice discoloration appearing at the soil level of the plant. Keep in mind that the infected parts of the plant will not be saved, so you have to cut them and get rid of them.
Once you have removed the damaged parts, you can then apply a fungicide on it to improve its health.
Applying fungicides on a damaged plant is of no use; it’s only going to delay its death for a little while longer.
Care and Prevention
More importantly, you have to worry about appropriate care and prevention of the plant as well. For starters, you have to make sure that you provide a rich and acidic soil for the plant to grow properly. You also need to evaluate the amount of sunlight that the plant receives.
The plant does not do well in bright sunlight, so filtered light is the best choice for the rhododendron. Another thing you need to do is choose a fast draining soil mix for the plant.
When water is allowed to drain quickly from the plant, it’s only going to reduce the chances of your plant succumbing to root rot in the future.
Ultimately, this will also prevent the foliage from turning yellow. Ideally, you also need to take care of the feeding process of the plant. You need to make sure that an acidic fertilizer is used for feeding the plant before it blooms, and that’s going to ensure that the plant remains healthy.
It’s recommended that you avoid overwatering from the top, as the plant could sustain considerable damage.
More importantly, you should make sure that you clean all of your garden tools, preferably sterilize them once they have been used before you use them again.
These are just a few things that you should know about taking care of the rhododendron plant and preventing any kind of discoloration on it.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.