What Diseases Affect Hydrangeas

The flower buds may even be fatally affected by this fungus before they bloom. Infected flower parts might also fall to the ground and infect the foliage.

Water-soaked patches on the blooms are one of the first indications. But these develop into sores that are reddish brown.

Botrytis is more likely to cause issues in cool, moist environments, such as several days of gloomy, muggy weather.

You can try to stop this illness by taking certain action. minimize the humidity. To avoid getting the flowers and leaves wet, avoid watering late in the day and just at the roots.

Keep your plants well-ventilated if you can. Pruning should be done on tightly spaced branches after correct spacing. As you prune, clean your pruning shears with bleach to prevent unintentionally spreading any disease.

Additionally, eliminate any dead or damaged flowers and leaves to stop the fungus from entering the plant. So that Botrytis cannot survive on the dead tissue, clear the area around the plant of debris.

Fungicides can be required if your issue persists. Iprodione and thiophanate-methyl are alternatives.

Leaf Spots (Cercospora species and Phyllosticta hydrangea)

On the base of the plant, cercospora appears as circular purple or brown patches. The leaves may turn yellow and drop off the plant as the diseases enlarge.

These illnesses can be avoided by watering without soaking the leaves. You can use liquid kelp, hydrogen peroxide, garlic oil, compost tea, or other remedies if your hydrangeas do become sick.

Anthracnose (Colletotrichum gloeosporioides)

This widespread fungal infection is more likely to affect plants that have received a lot of fertilizer.

The conditions that encourage infection are created by persistent rain or dense fog.

On the leaves or blossoms, the fungus causes huge brown dots that lighten in hue toward the center. One distinguishing indication is the angular development of dots around the veins.

Additionally, you can cure this condition with liquid kelp, hydrogen peroxide, garlic oil, or compost tea.

What does a hydrangea that isn’t healthy look like?

Anthracnose may be the cause of brown, tan, yellowish, or black patches on hydrangea leaves. It can also be recognized by the cankers that develop on the stems and branches. Hydrangeas are susceptible to anthracnose, thus it is important to remove and eliminate any dead or unhealthy plant parts. Mulch should also be removed from the affected area to prevent the spread of fungus spores. Use a fungicide made specifically for anthracnose, and carefully follow the label’s instructions.

What’s wrong with my hydrangeas?

The hydrangea is one of the more attractive plants for landscaping. No matter which species you prefer—bigleaf, oakleaf, panicle, or smooth leaf—they are typically thought of as being little maintenance and offer a colossal display of summer color. Common hydrangea illnesses can harm the health of the plant as well as the magnificent floral show for which they are famous. Recognizing common ailments and learning how to prevent and cure them is the first step towards healing a sick hydrangea.

You must first gather any hints if you want to figure out what is wrong with your plant. Are there any insects there? Does the issue only impact the leaves, or does it also damage the stems and flowers? After carefully examining the plant, you may begin determining what might be wrong with it and how to treat it.

Leaf spot diseases

Since the majority of sick hydrangea symptoms are foliar, the main fungus is frequently to blame. A fungus is the source of the leaf spots brought on by Cercospora, Alternaria, Phyllosticta, or Anthracnose. Although some occur during warm times, others form during cooler temperatures, they are most common in damp environments.

In most cases, the issue can be resolved by avoiding water buildup on leaves and using a potent fungicide.

A bactericide can be used to treat bacterial leaf spot. In all circumstances, removing and destroying contaminated leaves can help stop the spread of the disease.

Viral hydrangea diseases

Both mechanical and insect activity, which typically involves sucking pests, can spread viruses to plants. All hydrangeas are susceptible to 15 major viruses, but bigleaf cultivars appear to be the most frequently infected. Leaf mottling, chlorosis, blisters, rings, deformation, and stunting are signs of the disease. There are no recognized defenses against viral infections.

The best defense is a good offense. Before using pruning shears or knives on a plant, sterilize them. By practicing appropriate cultivation and getting rid of weeds and sick plant matter around the hydrangea, you can lessen the likelihood of pest infestation.

Systemic in nature, the infection will eventually spread to every component of the plant. The plant will eventually die and must be removed and killed in order to stop the spread of the disease to other landscaping plants.

Other hydrangea diseases

In ornamental plants, rust and powdery mildew are two frequent problems. Both have an impact on the overall beauty but neither will destroy the plant.

Similar in appearance to its name, powdery mildew is a fungus. It will have an impact on the leaves and the flowers, particularly the buds where the blossoms may be destroyed. If at all feasible, improve airflow, lower humidity, and get rid of any contaminated plant matter.

Another aesthetic drawback for hydrangea is rust. It manifests as crimson pustules on leaves and is caused by a pathogenic parasite. It might be transmitted mechanically or through plant material that has been contaminated. To control it, open the plant’s canopy and take off any damaged parts.

All varieties of hydrangea are susceptible to botrytis blight. On leaves, petals, and stems, there are water-soaked sores. Careful cultivation and cleanliness procedures, as well as the use of a fungicide, are required to treat a sick hydrangea with this disease.

What does hydrangea anthracnose look like?

Brown dots on the leaves are the first sign that your hydrangea has Colletotrichum gloeosporioides infection. These patches will be circular or just slightly irregular, as opposed to those brought on by other infections like Botrytis (also known as gray mold). Later, each spot’s center will turn tan.

The dots may take on an angular appearance if they are near a leaf vein. Whole leaves and flower petals may grow huge, erratic, dark brown dots that resemble blotches under the right circumstances.

Cankers, which are elevated edges with sunken centers, can also form on the stems. These can be dangerous because they can girdle or wrap the branches and stems, killing them over time.

New growth could be wavy or malformed, giving the branches a twisted appearance. The hydrangea can perish from a serious illness that has spread across the entire plant and resulted in malformed stems.

Why are the leaves on my hydrangea curling and becoming brown?

The main factor behind the browning of any hydrangea, including those in pots, is the same.

However, a few traits unique to hydrangeas grown in pots can raise the possibility of dark leaves and flowers.

The most common reason that potted hydrangea leaves become brown is that they are grown in pots that are too tiny and dry out too rapidly. The roots of hydrangea are thick, and they have a high requirement for soil moisture. The leaves will wilt, curl, and turn brown as an indication of stress if the soil dries out.

The capacity of the pot for potting soil, which holds moisture, is reduced if the container is too tiny.

When I notice a hydrangea in a container with brown leaves, I always check the roots because they are frequently confined by the pot and have less access to moisture.

As containers can dry out very rapidly on hot days and result in a dead hydrangea, it should be remembered that pots also require watering significantly more frequently than hydrangea planted in the garden.

  • The hydrangea should be repotted in a pot with a minimum 12 inch diameter and the same proportionate depth. This sized container guarantees that the hydrangeas have adequate soil for the roots to get the nutrients and moisture they need. It is worth checking to see if the roots are pot-bound as the hydrangea ages, though, as the root system can be rather vast. If so, plant the hydrangea in an even bigger pot.
  • Adding leaf mold to the potting soil will help. Leaf mold can assist in ensuring that your potted hydrangea has the ideal balance of moisture because it has an amazing capacity to hold moisture (even more so than compost).
  • As often as necessary, give your hydrangea a good soak to keep the soil constantly moist. In order to ensure that the soil is evenly saturated and that the water has reached the roots where it is needed, water the hydrangea thoroughly, letting any extra water trickle out of the drainage holes in the base of the pot.
  • In order to keep the leaves from turning brown during the hottest parts of the year, it can be necessary to water potted hydrangeas every day. Because of their huge, abundant leaves, hydrangeas have a high moisture requirement. In order to achieve the best moist soil conditions, watering hydrangeas once or twice per week in the spring and summer is typically the correct quantity.

The hydrangea should have enough resources with a larger container and more frequent watering to ensure that the leaves maintain a healthy green rather than turning brown.

Make sure the container is in a wind-free, sheltered location with dappled light or morning sun followed by afternoon shade.

You may always prune back any brown leaves or blossoms, or you can wait for the hydrangea to naturally shed them.

Why are the leaves on my hydrangeas yellowing and dropping off?

When in good health, hydrangea leaves are typically green, and the blossoms are eye-catching and vibrant. But when hydrangea leaves begin to turn yellow, isn’t it one of the telltale symptoms that something is wrong with this plant? What contributes to yellowing and how may it be treated?

Overwatering, excessive exposure to direct sunshine, or a lack of nutrients can cause hydrangea leaves to become yellow. Move the plant to a shaded location and drain the excess water from the pot to mend the yellow leaves. To maintain leaves healthy and green, feed the plant with nitrogen fertilizer and an iron supplement.

If you find a hardy type of hydrangea that can thrive in zones 3 and 8, and endure even some cold winter temperatures, hydrangeas are excellent plants.

How can a dead hydrangea be revived?

A hydrangea’s roots can be burned if too much fertilizer is used, which will likely result in the plant dying, turning brown, and drooping.

As such, hydrangeas are not heavy feeders and do not require annual feeding in the same manner as roses do, and doing so can actually be detrimental.

Hydrangeas frequently develop and flower to their full potential if they are planted in healthy soil or the soil has been modified with compost prior to planting.

The hydrangea should flourish if a 1-inch-thick layer of mulch is applied around it to assist retain moisture and supply nutrients to the soil (compost and leaf mould are ideal options).

Only in the following circumstances should fertilizer be used:

  • Planting the hydrangea in sandy soil (which is nutrient poor).
  • The hydrangea is in a pot or other container where the roots have used up all the nutrients in the soil.

In these two situations, it is recommended to use an all-purpose fertilizer with equal parts nitrogen, phosphorus, and potassium (NPK) that is applied once in the spring and is generally well-balanced.

The roots of your hydrangea can be burned by well-rotted manure, especially if it is added to the soil after planting. However, if the manure is made from poultry manure, it may contain a lot of nitrogen.

To prevent issues, I advise putting compost to the soil as a soil amendment (fresh manure is particularly harmful, always allow it to rot for a year or so before using manure on your garden).

If your hydrangea is exhibiting indications of stress as a result of being recently planted in soil that has been altered with manure, move it to a location with soil and compost, and it should recover.

Reduce the amount of fertilizer used and remove any discolored leaves or blossoms. To assist the hydrangea recover, thoroughly water it in an effort to dilute the soil’s water-soluble nitrogen.

Key Takeaways:

  • Most frequently, hydrangea deaths are caused by the soil’s lack of moisture. Because they need their soil to be continually moist, hydrangeas will droop or even die in a dry environment.
  • Drought, transplant shock, frost damage, and too much sun can all cause hydrangeas to perish.
  • If the pot base doesn’t have drainage holes, potted hydrangeas may succumb to root rot. Small containers may dry out too rapidly and limit root expansion.
  • Water hydrangeas liberally, cover them with compost mulch, and keep them out of the sun and wind to help them recover. To encourage healthy growth, remove any growth that has been sunburned or damaged by frost.