I find Hydrangeas one of the most confusing perennials as their green to unusually pale yellow leaf color differs within the varieties.
This proffers allure but sometimes makes it difficult to tell if your plant is in good shape or suffering from an unseen issue.
Generally, Hydrangea leaves turning yellow may indicate improper watering and light, nutrient deficiencies, temperature change, pests, and diseases. To fix the yellow leaves, schedule proper watering and lighting, feed the plant with the required nutrients, and monitor for diseases.
When a friend of mine was watering his Hydrangea, he caught the sight of a yellow leaf on the plant. It wouldn’t be a problem if the plant were of a yellow-leaved variety, but it wasn’t.
As soon as he informed me, I rushed to inspect the leaves, and fortunately, I succeeded in saving the pale Hydrangea.
The plant lived to tell its blossoming tale, so if you face a similar problem with your Hydrangea, keep reading to save the plant!
Table of Contents Show
- Is It Normal for Hydrangea Leaves to Turn Yellow?
- Why Do Hydrangea Leaves Turn Yellow?
- Should I Cut Off Hydrangea Yellow Leaves?
- How to Prevent Hydrangea Leaves Turning Yellow?
Is It Normal for Hydrangea Leaves to Turn Yellow?
Hydrangea can produce yellow leaves due to its deciduous habit, meaning it loses all its leaves from fall to winter annually.
Before falling, Hydrangea leaves fade to be yellow, turn brown, or even bear purplish color.
So, it is natural for Hydrangea to have yellow leaves if the reason is the plant’s natural phenology.
Besides, there are some Hydrangea varieties that possess yellow leaves naturally.
Hydrangea quercifolia and Hydrangea macrophylla are among the varieties that produce yellowish green and golden yellow naturally and respectively.
However, there are also evergreen varieties that carry green leaves all year round.
Hydrangea petiolaris, Hydrangea aspera, and Hydrangea paniculata are among the evergreen varieties that boast dark green leaves.
So any yellow leaf among the bunch could be concerning!
While it gets hard to know the issue at times, an experienced gardener can easily spot the difference through the seasonal change of leaves.
It is noteworthy if the Hydrangea’s leaves are turning yellow in spring or summer, which is not the natural time it should be doing so.
However, if the plant’s lower leaves are turning yellow, it may represent the plant is getting old, which is a natural process.
If the Hydrangea plants suffer yellow leaves due to reasons other than natural causes, you must seek the causes and immediate solutions.
Why Do Hydrangea Leaves Turn Yellow?
There are many reasons for your Hydrangea leaves to turn yellow; the common term for this is chlorosis.
The natural discoloration indicates that the Hydrangea has been receiving poor care.
So, let you be attuned to the details of the causes of unnatural Hydrangea yellow leaves.
1. Improper Watering
Wrong watering is the most common cause of Hydrangea leaves turning yellow. Both overwatering and underwatering fall under this category.
Although Hydrangeas love water, it doesn’t mean you create a wetland around it!
If you overwater the Hydrangeas, they can get smothered around the roots.
Overwatering can generate serious root rot conditions due to the soggy soil inviting the growth of fungi.
But, it is also important to keep Hydrangeas hydrated as it loves a few sips of weekly water during the growing season.
If you keep discarding this, the plant will begin to develop yellow leaves. Following this, Hydrangeas can start drooping and wilting.
Since both conditions can develop yellow leaves, you should spot the difference between the overwatered and underwatered plant.
If the leaves are yellowing and browning, with a pulpy or mushy texture, you are overwatering your Hydrangea.
Whereas, if the leaves are dry, crisp, and twisted with yellowing at the tips and edges, your Hydrangea is not getting enough water.
But, you can revive the same green vibes from the Hydrangea leaves by taking care of the watering schedule.
Immediate Steps of Revival for Overwatered Hydrangea
- If your Hydrangea has wet feet, stop the watering until the soil dries up.
- Move the potted plant to a shaded area and drain the excess water.
- If your Hydrangea is planted in garden soil, put a shade over the plant immediately.
- Put a stone layer at the bottom layer of the pot during planting or after repotting.
- Trim off the excess yellow leaves using sterilized pruners so that the plant can conserve enough energy to develop healthy green leaves.
- If root rotting is severe and the soil gives off a foul smell, change it with new soil with added perlite or sand to improve the drainage.
- Use mulch on the top of the soil to retain the moisture and keep the mulch until the leaves turn green again.
Immediate Steps of Revival for Underwatered Hydrangea
- Check the soil for dryness by taking a finger dip test by dipping your finger up to 1-2 inches into the soil. Water the plant deeply if the soil doesn’t stick to your finger.
- Dark soil indicates the plant is doing well with enough water, so skip the watering if this condition prevails.
- Water evenly throughout the soil until water drains from the drainage holes. Don’t water excessively, though.
- Increase the watering timetable from once a week to twice a week up to its revival.
- Plant your garden Hydrangea away from trees as this can increase the competition for water between the plants.
2. Incorrect Light
Hydrangeas are heliophiles, meaning they love the sun and tolerate up to 6 hours of daily partial sunlight.
Direct sunlight can scorch Hydrangea leaves, turning them yellow, brown, and wilted.
Besides, Hydrangeas don’t like the dark either, so growing them indoors in the dark is also not a good idea.
Insufficient light can also harm the plant with discoloration ranging from yellow to brown.
However, you can rescue the plant from yellow leaves by offering it the correct light and placement.
Immediate Steps of Revival
- If your plant gets yellow leaves, move it to a dark location.
- Place Hydrangea plants indoors near an east-facing window to get ample morning sunlight.
- Move the yellow-leaved Hydrangea away from the west-facing windows in the afternoon.
- Keep a shade above the plant if it is getting direct sunlight in the afternoon, and water frequently to retain leaf moisture.
- Pay close attention to the heat given by grow lights; otherwise, you will have leaf-scorched plants.
- You can grow Hydrangeas under fluorescent lights but since the grow lights are not as powerful as sunlight, increase the lighting period to 12 hours daily.
3. Nutrient Deficiency
Are you noticing the veins of the Hydrangea leaves remain green, but the entire lamina fading to yellow from the edge?
If so, the plant may not get enough iron in its diet.
Iron is an important catalyst for forming chlorophyll pigment, giving the leaves their green color.
But iron doesn’t work alone. Nitrogen and magnesium also aid in the leaves’ greening process.
Deficiency of all three nutrients can lead to the yellowing of the leaves in Hydrangea.
Additionally, if the young leaves bear a yellow hue, the plant is suffering from iron deficiency.
However, the yellowing of the older leaves indicates that the plant lacks nitrogen and magnesium.
So, if there is insufficient catering, you need to move your feet to follow the instructions below.
Immediate Steps of Revival
- Supplement the plant with iron-rich fertilizers, such as bone meal, blood manure, compost, or iron chelates.
- Provide the plant with nitrogen-rich fertilizer twice a year, once in early spring before the plant blossoms and once after the flowering season has ended.
- Use Epsom salts to provide the plant with the adequate magnesium it needs.
- Potassium hinders magnesium uptake, so ensure the fertilizer has less potassium if you revive the yellow leaves.
4. Temperature Stress
A temperature drop, along with the cold winds, can accelerate the yellowing of the leaves.
After the leaves turn yellow, they become brown, dry, and fall off.
Remember, Hydrangeas can only tolerate frost or cold if it is dormant. Before that, an alteration in optimum temperature can lead the plant to develop yellow patches.
Homegrown Hydrangeas like it if surrounding temperatures are between 10 and 22 degrees Celsius.
If it gets too warm, the edges of the leaves become yellow, turn brown and develop a crispy texture.
Jump into treating the temperature stress as soon as you find these symptoms.
Immediate Steps of Revival
- Relocate your potted Hydrangeas away from the north-facing windows in the winter.
- Stop cold drafts from getting inside the room where you keep the plants in the fall and winter seasons.
- Consider covering the garden Hydrangeas with frost blankets in winter to protect them from cold drafts at night.
- Move your potted plants away from radiators or coolers that can change the temperature.
- Cover the soil at the root line with mulch in fall, providing enough insulation for the plant in winter.
5. Soil Issues
Soggy and dry soil, improper pH, nutrient deficiency, etc., are all causes of yellow leaves that originate from the soil.
Hydrangea needs slightly acidic to grow and remain green. If the plant is inclined to the alkaline substrate, leaves can have a maximum chance of turning yellow.
Also, a pH value above 6.5 can be harmful to Hydrangea.
If you provide the plant with proper soil along with occasional changes, the issue of yellow leaves can be solved.
Immediate Steps of Revival
- Use sterilized soil before planting or transplanting to reduce the chance of disease infestation.
- Add draining elements like perlite or sand to give the soil additional drainage properties.
- Remove the excess salts from the soil by flushing it with distilled water 4 to 5 times to make it reusable.
- Maintain the proper acidity by adding lime to the soil for good foliage growth.
6. Horticultural Diseases
Hydrangea leaves are prone to many fungal, bacterial, or viral spores.
Bacteria and fungi are the main culprits whose infestation can turn the leaves yellow, but viruses are also a prominent cause.
For your ease, I have noted some bacterial, fungal, and viral diseases and their symptoms in the table.
|Diseases and Causative Organisms||Symptoms|
|Leaf Rust |
(Pucciniastrum hydrangea) - Fungal Infection
|Appearance of orange pustules on the bottom of the leaves followed by yellow spots on the upper surface.|
(Cercospora sp. and Phyllosticta hydrangea) - Fungal Infection
|Formation of circular brown or purple spots on the lower side of the leaves followed by entire leaf turning yellow and falls.|
(Erysiphe polygoni) - Fungal Infection
|White cotton-like growth appears on the bottom of the leaves and yellow spots develop on the surface.|
|Bacterial Leaf Spot|
(Xanthomonas campestris) - Bacterial Infection
|Leaf develop brown spots that have yellow edges.|
|Hydrangea Mosaic Virus||Formation of yellow mosaic patterns on the upper surface of the leaves.|
|Ringspot Virus||Leaves turn yellow followed by twisting of the leaf blade.|
Treating the diseased leaves is difficult as they cannot return to their original state.
Immediate Action After Disease Prevalence
- Move the diseased potted plant away from the bunch to prevent the spread of infection.
- If it is a garden plant, remove all the infected leaves using sterilized pruners and clean up all the debris.
- Identify the symptom and use the appropriate fungicide, bactericide, or viricide to treat the disease.
- Use insecticides that can kill a wide range of pests on the plants to prevent the spread of viruses.
Use Neem oil to prevent the spread of most fungal diseases, while it is better to use copper-based chemicals to prevent bacterial infections.
Should I Cut Off Hydrangea Yellow Leaves?
If the yellow leaves are unnaturally attached to Hydrangea stems, there is no better option except pruning.
The rust yellow leaves can invite pests, spread diseases, and consume the nutrition for nothing. So, cutting off helps Hydrangea shade unnecessary weight and coverage.
Also, you must cast off the sick leaves in spring and summer, avoiding the session in the winter or fall.
You can start the pruning with the following instructions.
- Sterilize the pruner with isopropyl alcohol and get ready wearing the gloves.
- Make a cut at the base of a stalk that joins the yellow leaves and stem.
- Avoid cutting healthy or green leaves.
- Also, if the plant has not had heavy leaves, do not remove more than 25 percent.
- After cutting the leaves, collect them in a container and pile them up to make compost.
How to Prevent Hydrangea Leaves Turning Yellow?
You need nothing but regular care to avoid unexpected yellow leaves on Hydrangea.
For your convenience, I have enlisted some quick instructions below!
- Provide Hydrangea plants with 3-6 hours of sunlight daily.
- Water 2-3 times at the rate of 1 inch (2.5 cm) each week throughout the growing seasons.
- Maintaining constant 40-60 degrees Fahrenheit will be enough.
- Allow the plant to receive around 40-45% humidity. If the humidity level drops, place the potted Hydrangea in the kitchen or bathroom.
- Hydrangeas require well-draining soil with pH ranging from 5.5 to 6.5.
- Feed all-purpose or balanced fertilizer with a 10-10-10 N-P-K twice a year, once in early spring and summer.
- You need to report Hydrangea annually if the variety is fast-grower or once every two years.
- Prune the plants immediately after the flowering period ends in summer, but do not need to trim later than the initial of August.
- Scale, Slugs, and Aphids are common pests that attack Hydrangea. So keep these away with neem oil or pesticide.
- Also, diseases, including Cercospora Leaf Spot, Powdery Mildew, and Botrytis Blight, can harm the plants. Before destroying the plants, apply fungicides on leaves every 10 to 14 days.
Yellow leaves in Hydrangeas do not indicate that the plants suffer, so you need to verify the hydrangea species you are currently growing.
If your Hydrangea shows unnatural yellow leaves, there must be some wrong with care requirements.
I have served all the possible reasons to make the yellow leaves so you can inspect your plant and treat it easily.
Hydrangea can show deceivingly severe symptoms, so you need to verify if the plant is dead or dormant.