Yellow Leaves on Rhododendrons – How to Cure

Rhododendrons are perennial shrubs that beautify our gardens. If you notice yellow leaves on rhododendrons, there may be a problem. Do not worry, this has a solution, but the first thing is to know why the rhododendron has yellow leaves. In this article, we will explain how to fix: Rhododendron leaves yellowing

What Causes Yellow Leaves on Rhododendrons

What Causes Yellow Leaves on Rhododendrons. Yellow leaves on rhododendrons can be caused by several factors, for example, it can be a problem of excess water or lack of water.

Rhododendron leaves yellowing. Also, if the plant suffers some kind of stress that may cause yellow leaves, the main thing is to know how to differentiate what the problem is so we can then start the appropriate treatment and thus save our rhododendron plant.

Did the yellow leaves appear before or after the rhododendron bloomed? There is some care that rhododendrons require due to their abundant flowering and the acid pH of the soil they need that we must be sure to provide the plant to prevent their leaves from turning yellow or brown and get an abundant flowering. So let’s review some rhododendron care tips to fix yellowing leaves.

How to Fix: Rhododendron Leaves Yellowing

Lack of nutrients affects flowering. So if the appearance of yellow leaves is accompanied by a decrease in flowering, it is an indicator of nutrient deficiency in the plant.

When does the rhododendron bloom? As there are many varieties of rhododendrons, the flowering period varies. However, the best known and most widely planted species bloom in the spring months (April and May). Before full flowering, remember to add liquid fertilizer along with the water or the granulated fertilizers mentioned above.

Yellow Leaves on Rhododendrons Due to Excess Light

Rhododendron leaves yellowing due to Excess Light. It is one of the most important rhododendron cares. Although it needs good sun exposure, it does not tolerate direct sunlight. Rhododendrons thrive best in semi-shade or, failing that, in a site that receives sunlight during off-peak hours.

Rhododendron leaves turn yellow due to sun exposure, sunlight tends to discolor exposed leaves. When this happens, adding nitrogen helps the leaves turn green again.

To avoid this problem, we must choose the right place to plant our rhododendron, this can be in a place with some shade or where it gets sunlight at off-peak hours.

yellow leaves on rhododendrons excess to light Rhododendron leaves yellowing
Rhododendron leaves yellowing due to Excess Light. It is one of the most important rhododendron cares. Rhododendron leaves turn yellow due to sun exposure, sunlight tends to discolor exposed leaves. We must choose the right place to plant our rhododendron,

Extreme Temperatures the Enemy of Rhododendrons

Rhododendron leaves yellowing due to high temperatures. Extreme Temperatures the Enemy of Rhododendrons. The excess of cold or heat is something that we will have to consider seriously in the care of the rhododendron.

Although it is not a demanding plant in terms of climate and is easily adapted to them, it is necessary to be vigilant if we live in a place of extremes.

But make no mistake. Rhododendron is part of the list of cold-hardy shrubs for the garden. However, you need to be cautious and plant it sheltered from frost.

If this is not possible, simply mulch it with mulch or dry leaves during the harsh winter months.  Prevention is better than having to figure out how to recover a plant after a frost.

Yellow Leaves on Rhododendrons Due to Excess Water

Yellow Leaves on Rhododendrons Due to Excess Water. Just as we will have to take time to decide where to plant it, spending a little more time on drainage is essential.

Rhododendron leaves yellowing due to Due to Excess Water. Despite being a water-loving plant, the rhododendron does not tolerate excess water in its roots. What’s more, exposing it to that extra water will only result in the death of the plant.

Without good drainage, you will have yellow leaves on rhododendrons, make sure the soil is adequate and if it does not have good drainage, you can add clay pellets or perlite to improve it.

yellow leaves on rhododendrons excess to water Rhododendron leaves yellowing
Rhododendron leaves yellowing due to Due to Excess Water. Despite being a water-loving plant, the rhododendron does not tolerate excess water in its roots. What’s more, exposing it to that extra water will only result in the death of the plant.

Acid Soil, One of The Rhododendron Care Vital for Its Development

Acid Soil, One of The Rhododendron Care Vital for Its Development. A detail is even more important than the planting site. Only if we provide our shrub with acid soil will it be able to grow healthily and, more importantly, bloom. The rhododendron can only unfold its flower clusters if it has the ferric nutrients it needs to do so.

If we do not know the composition of the soil, we can form the pH that this plant needs. Regular inputs of natural fertilizer or mineral fertilizers will suffice. This last step is very important because otherwise, we will have yellow leaves on rhododendrons.

Acid pH peat. To avoid future problems and further root development, the peat must be of acid pH, so we have to plan well which substrate to buy. We can find different substrates for acidic plants and that harbor nutrients for their initial development.

The soil pH of this type of peat is usually around 5-5.5 and it is beneficial for rhododendrons to fix yellow leaves.

As this perennial plant grows, we will need to either transplant it to the garden or adapt it to a larger pot. The first example is the most complicated since the post-transplant shock is worse. The soil has different drainage, a different pH, texture, hardness, etc.

A tip is to make abundant irrigation just after the transplant, with a small contribution of nutrients so that the roots that could have been damaged heal well and the emission of new ones takes place. Of course, it is essential to maintain proper drainage.

Yellow Leaves on Rhododendrons Due to Chlorosis

Yellow Leaves on Rhododendrons Due to Chlorosis. When the leaves are yellow but the region along the veins remains dark green, the plant is probably suffering from chlorosis.

When chlorosis is affecting Rhododendrons there is a characteristic deficiency of magnesium, nitrogen, or iron. In this case, the soil pH should be checked. How to measure soil pH.

Rhododendron is a species accustomed to slightly acid soils. Lime and high pH soils tend to cause iron chlorosis.

If we have a high pH in our garden it is necessary to provide a liquid iron chelate at the beginning of spring, which will be reapplied at the recommended dose in summer, at the time of maximum splendor.

It is important that the soil has good drainage conditions and that is something that can help you with the contribution of organic matter.

Before planting, it is advisable to mix the extracted soil with organic matter or decomposed compost in equal parts in the hole. This simple technique will allow faster development of the rhododendron roots and enough nutrients for its first flowering.

A very high pH hinders the plant’s ability to absorb the necessary trace metals. If the pH is close to 5.5, it is recommended to add Epsom salts. If this does not work, it is useful to add a source of nitrogen and chelated iron. Recommended articles to learn how to treat and fix iron deficiencies. Iron Sulfate for Plants: What It Is And How to Use It and Iron Deficiency in Plants – Ultimate Guide

The yellowing of young Rhododendron leaves with characteristic green veins is a clear sign of iron deficiency. It is very common in plants that are accustomed to acidic environments but have been planted in alkaline or high pH soils.

The solution is to apply any iron corrector, in the form of chelate, as it allows iron to be stable at different pH ranges.

Chlorotic yellow leaves are often a sign of iron deficiency and can be treated by using an iron sequence. Overfertilization should be avoided, as the leaf margin will likely become dry and brown.

We hope you find this article about how to fix: Rhododendron leaves yellowing useful.

rhododendron chlorosis Rhododendron leaves yellowing
Yellow Leaves on Rhododendrons Due to Chlorosis. When the leaves are yellow but the region along the veins remains dark green, the plant is probably suffering from chlorosis, which creates a deficiency of magnesium, nitrogen, or iron.

Rhododendron Leaf Drop and Rhododendron Lower Leaves Yellowing

Rhododendron Leaf Drop and Rhododendron Lower Leaves Yellowing. The fall of leaves that are not visually affected for any reason is a natural consequence of rhododendron growth, which replaces the lower leaves with the production of new leaves from the upper shoots.

Rhododendron Brown Leaves

Rhododendron Brown Leaves. When rhododendrons have excess moisture in the soil or substrate (especially in pot culture), the lack of oxygen to the roots causes slow and continuous rotting of the leaves.

An initial process is the loss of chlorophyll, resulting in a generic yellowing of the plant, but with a wrinkled and weak appearance of the leaves, which fall almost under their own weight.

As the days go by, these leaves become very flaccid and brown. A natural hormone known as ethylene is released and the leaves fall to the ground.

Recommended article for you How To Care for Rhododendrons – Guide

About Henry Morgan

We are the Morgan family, Henry, and Julia, both agronomists from the University of Michigan, where we met. We are experts in putting our hands in the soil and developing organic foods and improving production processes for decades. Likewise, we have worked for companies such as Mondelez International, BASF, Monsanto, etc. currently in our role as science writers for TheGardenStyle.com as well as advisors in promoting large scale food growing in urbanized areas. In this website, we share what we are most passionate about, gardening and farming. Enjoy and see real photos on our website.