How to Stop Hydrangea Leaves From Turning Red

hoya flowers deep pinkIt’s a bit frightening when the leaves of the plant you love change color to red. It’s good to know that, most times, the these leaves are the plant’s response to something that’s happening in the surroundings. If you can identify the issue that is causing stress to your plant, you’ll be able to make steps to fix the issue.

Hydrangea leaf leaves change color as a result of stress. The majority of the time it is due to extreme temperatures, whether cold or hot. If exposed to extreme temperatures the plant releases anthocyanin pigments which safeguard it in a variety of ways, and aid in prolonging the lifespan of the leaf.

I’ll explain the most frequent reasons for Hydrangea leaves changing color, and offer suggestions on ways to restore them to their green, lush splendor.

Causes of Hydrangea Leaves Turning Red and Dying

Anthocyanin Pigments

Most of the time the time that hydrangea leaves change color is due to producing anthocyanin pigments within the cells of the leaf. The plants produce these pigments when they encounter various stressors such as extreme temperatures excessive or too little light, or being attacked by insects.

There are more than 600 varieties of anthocyanins that naturally occur, and scientists are still trying to figure out exactly what they do to protect plants.

Research has shown that they function as a type of sunscreen that protects against harmful UV rays. They also increase the efficiency of photosynthesis, and also act as antioxidants, safeguarding against damage caused by free radicals.


One way to prevent the production of anthocyanins by plants is to make sure that they do not suffer from stress. For hydrangeas, this is placing them in a well-drained, rich dirt, keeping them well kept hydrated but not completely damp, and ensuring that they get sun exposure in the morning, but also get lots of shade in the hottest time during the summer.

If they are grown on the soil, they won’t require feeding, but they will be grateful for a compost mulch every year. For pots in the garden, using a slow release fertilizer specifically designed for hydrangeas that is applied every year is an ideal alternative.

Cold Weather

If the temperature drops, Hydrangea leaves usually turn red, before falling from the plants. It is a normal aspect of the cycle and usually not something to be concerned about.

Hydrangeas are deciduous. This means that during the autumn, their leaves fall off and then grow back in spring. In winter the plant can be dormant, meaning that it isn’t growing or requires any nutrients or water.

When they fall from the plants, the leaf leaves from deciduous trees produce lesser chlorophyll (the chemical that gives the green color of plants) and also more anthocyanins.

As the chlorophyll diminishes and we begin to see the red and orange colors appearing. This allows the leaves at the close of their lives to remain productive to last as long they can.


There’s no way to prevent the deciduous hydrangeas of your garden from losing their leaves during winter however, they’ll be perfectly fine outdoors with no protection unless temperatures fall below zero degrees Fahrenheit (-17.7 degrees Celsius). In spring, they’ll grow new growth that will be green and not red.

Certain varieties that Hydrangea are evergreen, which means they don’t change color and shed their leaves in winter. If you’d like plants with shiny green leaves all year long You could give Hydrangea integrifolia or the seemanii climber Hydrangea or Hydrangea integrifolia as well as the Hydrangea seemanii Hydrangea appearaniia give a go.

blue hydrangea with leaves in background

Growing In Full Sun

The best time to grow hydrangeas is when they have plenty of sunlight in the morning, when temperatures are cool and shade in the afternoon.

When your plants are exposed to full sunlight throughout the day it will defend itself by releasing anthocyanins, making the leaves turn red.

The pigments shield leaf cells from being damaged and aren’t harmful, however they do indicate of a plant that isn’t the best position.


Be sure that you plant your hydrangea in a place where it receives full sunlight during the daytime, but not during the afternoon. The majority of them require 4 to 6 hours of sunshine each day, with certain species needing more or less.

If you are unable to relocate the plants, think about ways to give it some shade during the hot period of the day. It is possible to plant other plants or trees, or construct any kind of structure, such as fencing to provide shelter.

Phosphorus Deficiency

Hydrangeas aren’t heavy feeders They are not heavy feeders, and excessive fertilizer may reduce the number of flowers that bloom on the plant, or harm the roots. If you notice your lower leaf on the plant have turned purple at the edges, it’s an indication of a deficiency in phosphorous.

It is important to remember that when temperatures in the soil drop to below 55degF (13degC), Hydrangeas struggle to absorb the phosphorous.

The problem is exacerbated due to the wet soil that can make it difficult for plants to absorb nutrients. Therefore, it is essential to ensure that your plant is in a drainage situation.

Keep in mind that during winter, the majority of Hydrangea go into dormancy and do not require taking in nutrients, therefore there’s no need to fret about the temperature of your soil preventing the uptake of phosphorous in the fall and winter.


Make sure you use plenty of compost that is high-quality for your Hydrangea and then apply compost mulch at least every two years. Compost is a source of all the nutrients that plants require in an easy-to-access form.

If your soil isn’t extremely poor in nutrients, it is unlikely that you need to apply fertilizer. If you do need to apply fertilizer, choose one specifically designed specifically for hydrangeas. Only apply it twice or once a year, in accordance with the directions.

Lack of Light

The hydrangeas that are growing in a place which is shaded may also have red leaves because anthocyanins increase the capacity cells to photosynthesis. If your plant receives less than 4 hours of sunshine a day and is becoming red, it could be the cause.

The absence of light typically results in pale growth that is oriented towards the closest source of light, or in certain cases, a mixture of red and pale growth.


Check to see if your plant gets sufficient sunlight. If it’s located in an area that is full of shade, relocate it to a more sunny location, but make sure that it isn’t in full sunlight.

If you are unable to move the plant, think about ways to increase the amount of sunlight it receives in the morning by, for instance, trimming other trees or plants that are in the vicinity.


The word “Hydrangea” comes in the Greek word to mean the word water (hydros) and Jar (angos). It should provide you with an insight into the water requirements of the plant!

While hydrangeas aren’t fond of moist soil, they require a significant amount of moisture. This can be a difficult balance for even the most experienced gardeners!

If you notice that your plant’s leaves are dry out, curling and changing color It could indicate that it requires more water.

Be cautious, however prior to increasing the amount of water you use ensure that the plant doesn’t suffer from root rot, as it can cause signs of dehydration.


If you’ve found out that your plant isn’t suffering from roots rot it’s simple to fix this issue. Simply give the plant water!

In summer, you’ll likely require watering at least twice a week. You might want to consider using mulch made of hardwood to aid in the retention of water.

The soil should be draining well since hydrangeas hate being soaked and are susceptible to root decay. In winter, cut down on the amount of watering, and only do so if the soil is completely dry.

Xanthomonas and Cercospora Leaf Spot

If you’ve noticed purple or red spots that are spreading slowly from leaf tips of your Hydrangea It may cause Xanthomonas as well as Cercospora leaves spot.

Xanthomonas can be described as a bacterial illness It is a bacterial disease, while Cercospora can be referred to as a fungal illness however, both share similar symptoms. They are spread by organic matter that is infected and are quite challenging to cure once they’ve established themselves.

Usually bacteria or spores transfer from the infected material to the plant via splashing water, such as rain, or when plant is watered by the above, however, it is also possible to transmit the infection through equipment or even through your hands. (Source: Michigan State University Extension)


Try to avoid both of these diseases by eliminating the fallen leaves as well as other organic matter that is decaying around the plant. This will ensure that there aren’t many places for fungal or fungal spores conceal, thus reducing the risk of getting sick.

Once it is established Once it is established, once it is established, a Xanthomonas infection can be difficult to cure. The bactericide isn’t effective on the market therefore the best thing to do is to remove the affected parts of the plant and pray for the best results.

Certain plants are able to survive the disease, while others do not. If the infection is serious, it’s recommended to eliminate the plant.

Cercospora leaf spot is treatable by fungicides if you recognize the disease in time. When less than percent of the plant is affected, chances of survival are high.

If your plants are infested with a lot of disease It’s best to remove them and then attempt to do it to do it again. Be sure to not reuse pots or soil from affected plants without first sterilizing them.

Phytophthora Root Rot

The Phytophthora fungal infection that causes roots rot is thriving in moist soil. It can be easily spread by splashing water or soil that is infected.

It is a major threat to all plants , and is an issue specifically for Hydrangeas due to their need for water. When your plants are located in the soil that is flooded, it’s likely to suffer from root rot.

Root rot is usually the cause of dehydration because it blocks the plant from absorbing the water it needs through its root. If your plant is suffering from dry, drooping leaves, but is receiving ample water supply, then root decay could be the cause.


Make sure certain that your Hydrangea is located in a well-drained soil. Do not let it remain in soil that is wet for any period of duration. Think about moving it or improving soil drainage in the event that it becomes saturated.

After it has established itself the root rot can be difficult to cure. It is possible to remove the affected roots, which appear brown and slimy and replanting them in a well-drained soil and avoiding the watering for a few days.

The plant could be able to recover. But root rot is an end-of-life sentence for many plants. It might be best to get rid of the plant and try it again.

Should You Worry About Hydrangea Leaves Turning Red?

Since the red leaves are a sign of stress, they’re usually an indication that the plant is unhappy with the situation. Although it’s not a cause to be concerned, you should look into the root of the problem – then decide on how to fix it.

For instance, leaves that are red in autumn are common and don’t require any kind of treatment. Red leaves that are caused by excessive sun, however they are a sign that your plant is more content elsewhere. Red leaves that are caused by root rot indicates that your plant needs immediate attention.



Went from a bad gardener to a half-decent one over 10+ years. Super happy to share my tips and tricks with you :)