Hydrangeas are recognized for their resilience to pests and diseases. However, Several causes may lead to plant health issues. In this situation, it is critical to effectively eliminate them as soon as possible.
Nevertheless, even when its leaves are a secondary attraction, leaves turning brown is a common hydrangea problem that you may encounter.
The primary cause of hydrangea leaves turning brown is a shortage of nutrients in the soil. This behavior is often seen in branched hydrangea when grows for a lengthy period of time in one location (more than 5 years) or when the soil is deficient in trace elements, particularly iron. Besides, fungal diseases, temperature stress, transplant shock, pest infestation can cause hydrangea leaves to turn brown.
I’ll go through each potential cause that may be making your hydrangea leaves turning brown, concentrating on the most frequent ones.
|Causes of Hydrangea Leaves Turning Brown||Signs||How to Fix|
|Fungal Diseases||Gray Rot: Delicate gray hue that ultimately Leaves dries up.|
Downy Mildew: dark brown greasy patches on hydrangea leaves.
Rusts: Appears as tiny yellow dots that quickly become brown.
|Spray Use copper-based fungicides and avoid overwatering.|
|Root Rot due to Overwatering||Leaves begin to turn yellow and eventually brown.||Only water when the top 1-2 inches of potting soil is dry|
|Underwatering||Without water leaves dry out and turn brown gradually.||Regularly check the soil moisture level and water when the topsoil becomes dry.|
|Insect Infestation||Brown patches on the stem and leaves.||Apply neem oil or horticultural oil and maintain a healthy environment.|
|Too Much Heat||Hydrangea plant cells die and cause turning the leaves brown||Plant your hydrangea in partial shade.|
|Sunburn||The edges of the leaves and middles of the leaves are scorched.||When the sun is too bright, use shades to protect your hydrangeas.|
|Cold Drafts||Leaves turn reddish-brown and yellow.||Provide a hedge around your plant to serve as a shield.|
|Fertilizer Residue or Salt Buildup||Damages the root and leaves turn brown||Flush out the excess fertilizer with a lot of freshwater.|
|Transplant Shock||Leaves droop and turn brown||Be careful not to damage the roots during transplanting.|
|Deficiency or Excess Nutrient||The tips of the leaves turn brown and dry starts with the bottom leaves.||Apply organic fertilizer not more than twice a year.|
|Low Humidity||Leaves wither and dry||Keep the soil moist and mist the leaves|
Causes of Hydrangea Leaves Turning Brown
Diseases of Hydrangea Cause Brown Leaves
Pathogenic fungi are to blame for such various diseases. They pose a significant risk, and their treatment can be a lengthy and complicated procedure.
Regardless of the disease’s earliest phases, they all have one thing in common: fast propagation throughout the plant and the destruction of all of its pieces (from leaves to stem and inflorescences). High humidity and early contamination of the soil and adjacent plants are common causes of fungal infections.
Here are some common fungal diseases that can cause leaves to turn brown:
Primarily affects leaves, resulting in a delicate gray hue that ultimately dries up, forms brown patches, and crumbles into dust. Waterlogging caused by overwatering or overcrowding of hydrangeas is the most common cause of rot.
Primary signs of downy mildew are dark brown greasy patches on hydrangea leaves. You can treat this disease very easily, but only in the early stages.
If you can not the fungus right away, it swiftly spreads to all areas of the f and is nearly hard to eradicate. High humidity and high temperatures (20 °C/68°F) are ideal circumstances for the growth of downy mildew.
Septoria is a fungus that causes tiny (up to 5 mm) bright patches with a brown border. The disease swiftly spreads throughout the plant during its growth. Septoria blight is more common in the summer when the weather is chilly and wet.
Most rusts are caused by excess water and nitrogen in the soil. It appears as tiny yellow dots that quickly become brown. Such circumstances cause leaves to wither.
There is rusty dust inside the infected part, which is mycelium. It can disseminate through wind and can infect all your plants eventually.
How to Fix:
- Keep the leaves dry, do not water from top.
- Avoid overwatering. A moist environment is favorable for fungi to multiply.
- Use copper based fungicides.
For the treatment of fungal diseases. Here are the fungicides I recommend:
|Name of The Fungicide||Amount||Amount of Water|
|Bonide 811 Copper 4E Fungicide||1-4 tablespoons (.05-2.0 fl oz)||1 gallon of water|
|Garden Safe Brand Fungicide3||2 tablespoons (1 fl oz)||1 gallon of water|
|Southern Ag – Liquid Copper Fungicide||3-4 tablespoons||1 gallon of water|
Overwatering Leads to Root Rot Disease
Fungal infections are caused by frequent watering, which prevents even the soil’s surface layer from drying out. Your hydrangea’s leaves begin to turn yellow, and the roots begin to rot in this case.
Nutrients will not be properly channeled without water. Photosynthesis will not occur without water. On the other hand, when water is too high, plant cells will burst and die.
These are adverse effects of an imbalance water supply that could eventually lead to the death of your hydrangea.
How to Fix:
- Regardless of the hydrangea-growing choice, the water your plant in a methodical and gentle manner.
- Ensure funtioning drainage holes and a tray to remove excess moisture while growing in pots.
- Only water when the top 1-2 inches of potting soil is dry. Watering ferquency will depend on season, temperature, humidity etc. Water more frequently during summer.
- Always make sure that the soil is completely dry before watering again to prevent root rot.
Undwerwatering Can Cause Hydrangea Leaves Turning Brown
The hydrangea becomes vulnerable to insects if the soil dries up, especially when the temperature increases. Sap sucking insects suck the life out of the leaves and causing them to turn brown.
Also, due to extremely dry soil, the root system will struggle to intake moisture as well as other nutrients. Without water and nutrients, the leaves will suffer and turn yellow or brown gradually.
In this case, the leaf tips and edges tend to turn brown first because it is hard for the plant to reach the edges and tips with water and microelements.
- Mulching with peat, sawdust, or spruce branches might help to keep the soil wet.
- Regularly check the soil moisture level and water when the top soil becomes dry.
In hydrangea, common pests are scales, slugs, aphids, beetles, and fruit worms. Most of them target the stems and the leaves by feeding on them, cutting them, or laying their eggs. Here are some common pests that can cause hydrangea leaves to turn brown:
Aphids eat by sucking sap from the plant’s sensitive portions. Despite their huge numbers, they are normally controlled by natural predators (ladybugs, lacewings, and others). Foliage drying and yellowing are the earliest symptoms of aphid attack.
A spider mite is a pest that feeds on plant sap and is virtually undetectable to the naked eye. In dry, hot conditions, the most vigorous reproduction occurs.
If you inspect carefully you can see a thin cobweb, as well as the development of brown patches on the stem and leaves in the afflicted parts of the plant. After that, your hydrangea leaves dry out and curls.
How to Fix:
- Regularly check the plants and manually remove any pests that you see. Prevention is better than cure so it’s better to remove them before they cause more harm to your hydrangea.
- Apply pesticides when necessary. When you find it difficult to manage the pests, you can apply pesticides to control them. Be careful though not to overdo its application as it may be harmful to the plants.
- Create a healthy environment for your hydrangea. Pests do attack when the environment gets favorable for them to thrive.
Too Much Heat
Plants lose more water when it is too hot. If this situation persists and water is not quickly supplied, the plant cells will shrivel. That’s why you’ll frequently see the leaves curling up and drooping.
Tips of the hydrangea leaf dried out due to the significant variation between day and night temperatures.
A rapid decrease causes stress, and as a result, metabolic activities in plant tissues significantly slow down.
This does not cause severe harm to your hydrangea, but it may have a detrimental impact on large-leaved types.
Hydrangea doesn’t like varying temperatures especially the sudden increase. The ideal temperature for the hydrangea to thrive is 68-72 °F (20-22 °C).
Too much temperature cause plant cells to die and consequently turning the leaves brown. These brown leaves are often crisp and dry when touched due to their dehydrated condition.
How to Fix:
- Plant your hydrangea in a partial shade. Alternatively, if your hydrangea is getting direct sunlight you may transplant from its current location and place it somewhere cooler.
- During hotter days, increase your water supply to adjust for moisture loss resulting by a greater transpiration rate.
Despite the fact that hydrangeas like bright light, they do not withstand direct sunshine. Excessive sunlight may cause the hydrangea’s leaves to turn brown and fall off over time.
Sunlight is a source of energy for leaves to perform photosynthesis. However, not all wavelengths in light are beneficial to plants.
The edges of the leaves, as well as the middles of the leaves, are scorched as a result of exposure to sunlight. And that is how sunburn appears on the leaf’s surface.
How to Fix:
- Avoid a location that has direct or prolonged exposure to sunlight.
- When the sun is too bright, use shades to protect your hydrangeas.
- Give sufficient water as needed to avoid dehydration.
You May Also Enjoy: Hydrangea Leaves Turning Yellow (8 Causes And How to Fix It)
The ideal temperature for hydrangeas at home is between 22-24 °C (68-72 °F); higher temperatures cause the leaves to turn reddish-brown and yellow. The effects of cold drafts in plants include wilting, browning, and dying of the plant.
Hydrangeas have a hard time coping with drastic temperature fluctuations and strong drafts. You should place the plant behind fences and tall shrubs on the street.
How to Fix:
- Avoid a location where the cold air is directly hitting the plant like in front of an air conditioner, an open door, or a window.
- Provide a hedge around your plant to serve as a shield.
Soil Lacks Water Holding Capacity
The water holding capacity of the soil determines the amount of water it can hold for the plant’s consumption.
It will dictate how much water it absorbs and stores during watering so that the plants will have water to use in between.
When soil lacks water holding capacity, the tendency is it will easily lose water. When this happens, plants will suffer from drought. The plants will not receive enough water to sustain their processes.
The wilting of plants leads to the browning of the leaves in hydrangea. At first, you’d observe that the leaves are limping. Little by little, it will turn brown and crisp.
How to Fix:
- Enhance the texture of the soil by adding more organic matter. Organic matter acts like a sponge that absorbs and holds more water in the soil. The ratio of organic matter needed will depend on the nature of the soil you are using for your hydrangea.
- Add mulch on top of the soil. This will slow down the release of moisture and at the same time act as a source of organic matter for the plants to consume later in time.
You May Also Enjoy: Why Is My Potted Hydrangea Wilting? (10 Causes and Solutions)
Fertilizer Residue or Salt Buildup
Your hydrangea might need a little help so you’ve added fertilizer to aid its growth. It’s totally okay to add sources of nutrients because they need them. However, it has to be done carefully.
Too much fertilizer, especially those that are fast-release, present in the soil causes salt to build up. They also increase the soil’s acidity. High salt concentration causes cells to shrink and die.
This phenomenon leads to the browning of the leaves and the death of the plants. That’s why you’d notice that after just a few days, leaves will start appearing burnt when there’s too much fertilizer applied.
How to Fix:
- Apply fertilizer only when necessary. Hydrangea will need fertilizer only once a year and that’s during early or late spring or middle of summer.
- Apply fertilizer based on recommendations. Generally, a complete fertilizer can be added around 2 to 3 inches on topsoil and should be covered. Manufacturers will surely have detailed instructions on how to do it so be careful to follow it.
- Choose organic fertilizer. They are slow-release and do not harm the plants. You can put as much as you can without worrying about burning up your hydrangea.
It’s normal for plants to experience shock after transplanting. The roots will take time to establish themselves in the new environment. During this transition period, your hydrangea will appear to be wilting and turn brown eventually.
It’s also normal for the older leaves to turn brown, die, and shed off. That does not necessarily mean the plant is dying. Wait a little more time until new leaves sprout.
How to Fix:
- Be careful not to damage the roots during transplanting.
- Trim off the leaves above in proportion to the pruned portion of the root below ground.
When roots aren’t as free as they should be, the plant’s health is at stake. This is because the plant’s ability to take up water and nutrients are being limited.
Roots that are constricted will have difficulty coping with stressful environmental conditions.
Due to limited capacity, a hydrangea with constricted roots will either suffer from dehydration or nutrient deficiency.
Both of these phenomena can lead to the browning of leaves and deterioration of the entire foliage of the plant.
How to Fix:
- Make sure to transplant the hydrangea in a pot that is proportional to the size of the roots. Avoid using pots that are too small.
- Trim off some of the roots before transplanting but be careful not to damage it.
- Provide enough soil for the roots to anchor on.
Deficiency or Excess Nutrient
Hydrangea brown leaves are a sign that may signal potassium deficiency in the soil. When this component is deficient, the tips of the hydrangea’s leaves turn brown and dry. This first appears in the bottom portion of the bush and then gradually extends to the top.
In addition, a shortage of iron can cause the tips of the leaves to dry down owing to a disruption in the photosynthetic process. In this scenario, the color intensity of the leaves fades first, while the veins stay dark green. Then they begin to dry out.
Excess fertilizer has a negative impact on hydrangea. It might also cause the leaves’ tips to dry out. As a result, near the end of the flowering period, reduce the fertilizer dosage and a number of dressings.
How to Fix:
- It is important that the soil is well amended with organic matter to make sure that it has sufficient nutrients to start with.
- Fertilize when necessary. Through time, the nutrients in the soil get depleted. To sustain the growth of your hydrangea, a fertilizer supplement is needed.
Light is a source of energy for your hydrangea. A plant that is sufficiently receiving light will have leaves that are bright green in color.
Hydrangea benefits from diffused bright light, which promotes lush foliage and abundant flowering. By putting the plant on a south or west-facing windowsill, you may artificially extend their sunshine hours.
But keep in mind, the scorching heat causes permanent burns on the leaves and appears lifeless due to the prolonged darkness.
With inadequate light supply, the leaves will have difficulty manufacturing their own food. If not treated well, the plant will starve and die. You’ll notice that leaves will start to turn brown in color because the cells are dying.
How to Fix:
- You should consider planting hydrangeas near houses or fences. Hydrangeas prefer the early morning light to the afternoon sun.
- Hydrangeas flourish in a safe location with morning light and afternoon shade.
- In case of need, use artificial light. Winter will limit the hydrangea’s exposure to sunlight. To meet the plant’s needs, add additional light sources to the room.
You May Also Enjoy: How to Save Overwatered Hydrangea (Step By Step Guide)
Inadequate humidity means that there is a lower concentration of water vapor in the air. This leaves extra room for air to accommodate more vapors.
Hydrangeas tend to evaporate more water when the humidity is low. As water is lost quicker than it is used by plants, soil water storage is quickly depleted. This causes leaf withering and dryness. Consequently leaves turn brown.
Indoor plants need at least 40 to 50% humidity level. Maintaining such a level can be challenging but there are ways in which you can raise the humidity inside a room.
How to Fix:
- Make use of a humidifier. The humidifier increases humidity by releasing water vapor into the air.
- You can mist the leaves when then air is too dry. This will increase the amount of moisture in the air and reduce the rate of water loss in the leaves.
Potted Hydrangea Leaves Turning Brown Due to Poor Drainage
One cause of browning in leaves is rotting roots. Rotting is a result of waterlogging in pots.
If your soil is not well-drained or the holes aren’t good enough to drain the water, then your hydrangea is prone to root rot.
Poor drainage can be a result of poor soil mix, especially if it has no good spaces to hold oxygen.
Limited or no draining holes at all can be another reason. A pot that is too large holding extra water can be another one.
How to Fix:
- Start with a good soil mix. Always add organic matter especially if the soil has higher clay content. This will increase the soil’s draining capacity.
- Use a pot that is size appropriate to your hydrangea. A size that is too large or too small is neither good.
- Make sure the pots have enough holes to drain water freely.
How to Maintain Healthy Hydrangea Leaves?
Leaves are indicative of the plant’s health. It’s important to pay close attention to the symptoms it shows at the early stages to be able to find immediate solutions to its problems. A healthy plant will grow healthy leaves.
Whenever you notice any abnormalities, be quick to diagnose the problem and provide a quick fix.
(Source: Tennessee State University)