Why are hydrangea leaves turning yellow?
People love the plant’s blossom because of its pompom like flowers, making it’s beautiful and visually appealing.
Typically, hydrangea leaves are green when healthy, so if they start turning yellow, it is an alarm that something is wrong (source).
The yellow leaves are not that appealing; that’s why you have to look for a way to fix this problem.
It has colorful and beautiful flowers, and once the leaves start changing color, the beauty tends to fade away.
Might you be wondering, what really causes the leaves to turn yellow?
Just like Cucumber, Hydrangea leaves turn yellow due to several reasons.
In this article, I will discuss the causes of hydrangea leaves turning yellow and how to fix it.
Hydrangea Leaves Turning Yellow Causes
There are several causes of the hydrangea leaves turning yellow (source).
Let’s get started;
1. Leaf scorch
One of the causes of hydrangea leaves turning yellow is leaf scorch, which is due to too much direct sunlight.
The commonly affected leaves are those that are more exposed to the light.
A hydrangea plant thrives well in partial sunlight; that’s why you should keep the plant in the shade during the day.
Apart from turning yellow, the leaves may start dropping for the plant, leaving the plant with fewer or no leaves.
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Overwatering is a common reason for yellowing leaves in hydrangea plants and other plants in general.
As much as the hydrangea plant likes water, it does not thrive well in excess water conditions.
Most plants grow best in well-drained but moist soil.
If the ground or pot does not have good drainage, the leaves start changing slowly from green to yellow.
The excess water drenches around the root area, leaving the plant soggy and unable to breathe.
Later the plant starts having stunted growth, the roots rot, which may lead to fungal disease.
Root rot will eventually lead to the death of the plant.
To fix this problem, ensure the soil is well-drained without allowing it to dry since it may also lead to the yellowing of leaves.
Just like overwatering, underwatering may lead to hydrangea leaves turning yellow.
Underwatering may be due to poor watering schedules where you take too long to water your plants.
Very little or no moisture leads to wilting, droopy, and yellowing of the leaves.
The best way to fix this problem is to ensure your hydrangea plants are moist around the root area all the time.
However, be careful not to overwater the plants since it can still lead to the leaves yellowing.
4. Iron Deficiency
If you notice hydrangea leaves turning yellow, it may be due to iron deficiency.
Iron is a nutrient that has a crucial role in making leaves green and other parts.
Iron deficiency is called iron chlorosis, and it comes about if the hydrangea plant does not have enough iron supply.
Iron deficiency signs in a hydrangea plant include.
- Yellowing is on both the new and old and expanding leaves
- All leaf parts turn yellow, leaving the veins green
Iron chlorosis is commonly due to watering plants using hard water.
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If you see the hydrangea’s new leaves turning yellow, but the veins are still green, iron deficiency is the first thing to think of.
5. Low Soil Acidity
Low soil acidity may be the reason your hydrangea leaves are turning yellow.
These plants thrive well in acidic soil; that’s why it recommended you do a test.
6. Fungal Disease
Fungal diseases are noticeable through the leaves and roots of a plant.
These diseases lead to root rotting, which means that the plant will not feed nutrients and water from the soil well.
It will eventually lead to the yellowing of the leaves as a result of a lack of water and nutrients.
You can reduce the chances of further spread of this disease by removing the yellowing and fallen leaves from the plant.
Once you see the hydrangea leaves yellowing or drooping, check out for fungal infection, it may lead to plants dying if not dealt with early.
Another fungal disease sign is a leaf spot, which can inform brown, purple spots on the leaf underside.
One way to reduce this disease’s possibility is by ensuring you water the hydrangea to the soil level and avoid watering the leaves.
7. Nitrogen Deficiency
Common signs of nitrogen deficiency in plants are stunted and growth and yellowing of older leaves.
This problem is easy to take care of by applying nitrogen-rich fertilizer.
In case after application, you notice that there is no change, check out your watering schedule.
It is possible that the nutrients are being flushed out of the soil if the pot has too large drainage holes.
Overwatering the plant also draws the nutrients out from the top of the pot.
Nitrogen deficiency can be fixed by adding ammonia sulfate to the soil by scattering it around the hydrangea plant.
Ensure you add some water to the soil, which will help improve the soil’s nitrogen content.
How to Fix Hydrangea Leaves Turning Yellow
Add Iron Supplement
After discovering that iron deficiency is the cause of your hydrangea leaves turning yellow, add an iron supplement to the soil.
Supplement using iron chelates and ensure you do not overwater it.
Overwatering flushes the nutrients from the soil, leaving with insufficient nutrients to feed the whole plant.
Ensure the Right Soil Moisture Level
As I mentioned earlier, both underwatering and overwatering may lead to leaf yellowing.
Ensure the soil has the proper water level by ensuring the soil does not dry completely and avoid making the soil soggy.
If you don’t have too much water for watering your plants, mulching will be an excellent idea to retain moisture.
In case the problem is overwatering, reduce the frequency of watering and ensure there is good drainage.
Use a drainage layer made of broken bricks, sand, or small stones.
Provide Access To Partial Sunlight
Hydrangeas love partial sunlight instead of direct sunlight.
Excess sunlight leads to a lot of water loss through the leaves, which eventually causes wilting, drooping, and sunburns.
Expose the hydrangea plant to direct sunlight for around 5 hours, then keep it in the shade.
However, avoid keeping it in darkness since it does not grow well in such conditions.
Apply Mineral Fertilizers
If it comes to your attention that insufficient nutrients are the problem, add fertilizers to the soil.
Be keen to determine which mineral is really missing so that you use the right fertilizer.
If iron and nitrogen is insufficient, you can use milorganite to help your plant gain iron and nitrogen supplements
In the case of iron alone, use iron chelates and ensure you do not overwater the plants when feeding the plant with the nutrients.
Test for soil PH
When the soil has low acidity, the plant leaves tend to turn yellow.
If the hydrangea soil does not have enough acid, water it with water mixed with citric acid and use mulching to retain soil moisture
The right PH that hydrangea tend to thrive well ranges from 5.5-6.5
Final Thoughts on Hydrangea Leaves Turning Yellow
Hydrangea is a beautiful plant to plant indoors when well taken care of.
The above are some of the causes of hydrangea leaves turning yellow and how to fix them.
Some of these causes are easy to fix like overwatering and underwatering through regulated and proper watering.
Check out for the above problems in case your plant’s leaves are turning yellow.
Always take proper and timely care for your plants while taking all the preventive measures.
Check out for diseases and infections before it is too late for the plants healthy.
Hello, I’m Tanya, the voice and passion behind Smart Yard Guide. With a lifelong love for nature and a keen eye for design, I embarked on this journey to share my expertise and experiences in landscaping, gardening, and outdoor design. As a dedicated homeowner myself, I understand the joys and challenges of curating a space that seamlessly blends nature with human creativity.
My background in horticulture and landscape architecture has given me a solid foundation to explore innovative ideas while respecting the time-tested principles of outdoor design. From selecting the perfect plants for your climate to mastering the art of harmonious hardscaping, I’m here to guide you every step of the way.