Best Way to Treat Anthracnose on Hydrangea – Top 4 Fungicide

An entire hedge of hydrangeas around your property can do a lot to improve the overall aesthetic, even if you don’t have a bunch of other plants around. However, while they aren’t very tough to take care of, hydrangeas tend to be vulnerable to fungal infections that negatively impact the leaves and flowers.

A common fungal infection is anthracnose (caused by the Colletotrichum gloeosporioides fungus). This type of infection is found around the globe and attacks temperate and tropical plants. The said infection causes flowers and leaves to turn brown. Anthracnose on hydrangea should be treated as soon as possible to stop the spread. This fungal infection is known to attack bigleaf hydrangeas the most.

For people wondering about the best ways to treat anthracnose on hydrangea, we have created an entire guide that will help you not only treat the infection but also prevent and diagnose it.

The Symptoms of Anthracnose on Hydrangea

If you have hydrangeas around, the first thing you should learn about is how to identify the symptoms of an anthracnose infection. The first indication is the presence of brown spots on the hydrangea leaves. The shape of the spots can be circular or a bit irregular. Also, the center of every spot will turn tan a bit later. Take note; if the spots end up bordering a leaf vein, you can see an angular shape.

If the infection is allowed to spread, the leaves and flower petals can have large and irregular dark brown spots that resemble blotches.

The stems can be impacted, too. They can develop cankers, which occurs when stems develop sunken areas that also have raised margins. Cankers can be quite troublesome because they can kill stems and branches.

Severe infection can lead to deformed stems, which can kill hydrangeas.

Symptoms of Anthracnose

Anthracnose vs. Cercospora

It’s easy to confuse spots created by anthracnose with spots from Cercospora. However, there are a bunch of differences between the two.

Even though Cercospora spots are circular as well, they tend to be purple when they begin forming. As the spots mature, they grow larger and end up developing lighter centers that resemble frog eyes. Entire leaves can end up turning purple as the infection continues.

Take note; leaves that turn purple due to Cercospora shouldn’t be confused with purple leaves due to phosphorus deficiency.

Furthermore, if hydrangea has a Cercospora infection, the spots will first begin on the lower leaves. In contrast, due to an anthracnose infection, the hydrangea can have spots appear at the top, and the bottom leaves at once.

Another significant difference is that the Cercospora doesn’t infect flowers.

Environmental Conditions Leading to Anthracnose Infection

An anthracnose infection favors hot, wet conditions. This is because the high level of moisture assists with the spreading of spores to infect the entire plant and other hydrangeas. Chances of infection can greatly increase due to several wet days. The preferred temperature for this infection is 75-90 degrees Fahrenheit (23.8-32.2 degrees Celsius).

You should know that if the plant has infected leaves or the ground beneath the plant has infected leaf debris, there will be massive spore formation in fruiting bodies. Rain or watering such a plant yourself will release the spores and lead them to infect other plants.

Heavy fog and dew can also assist with more extensive spread.

Even if your hydrangea isn’t infected yet, if you’re living in wet or moist weather, your hydrangeas are at a higher risk of being infected due to other infected plants nearby.

How to Prevent Anthracnose Infection

You can keep your hydrangeas safe if you know the proper preventive measures.

Watering the Plants

Anthracnose infection is spread by water. That’s why you should ensure not to wet the flowers and foliage when you’re out watering the plants.

It’s recommended that you water plants by pouring water at the base. Remember to give your hydrangeas a lot of water.

Don’t Over-Fertilize

You should also avoid over-fertilizing your hydrangeas. This is because hydrangeas that have been over-fertilized can be more vulnerable to an anthracnose infection.

Management of Anthracnose Infection

If a plant has been infected, it can be challenging to get rid of the said infection. However, the good news is that it’s possible.

The moment you notice the spots due to anthracnose, you should quickly take healthy cuttings from the plant. Such cuttings will be your backup plan to keep growing hydrangeas in case you are unable to get rid of the infection from the original plant.

Other management steps include:

Pruning and Sanitation

You should prune the infected plant tissue to prevent the infection from spreading to other parts of the plants. Simply trim away the unhealthy parts and throw them away. However, don’t go overboard with the pruning because the hydrangea might not recover.

Once you prune a plant, you should sanitize the shears before using them to prune another plant to avoid infection.

Once you have pruned all the plants that require it, you should remember to properly sanitize the pruning shears by using a solution made from 10% bleach or 70% rubbing alcohol.

The plant debris on the ground can serve as a place for the infection to stay dormant during winter. And once spring comes, the infection will live again to start infecting plants again. That’s why you should collect fallen leaves and clear away plant debris from under the hydrangea.

Take note; you should never place plant debris in your compost pile.

Pruning and Sanitation hydrangea

Use Fungicides

Fungicides are an effective way to prevent the spread of anthracnose. You should use fungicides after you have pruned the plants. There are numerous fungicides for you to choose from. Remember to follow the instructions on the fungicide’s packaging.

It’s recommended that you use fungicides on the plant after a 10–14-day interval during summer. Of course, you can spray more if the infection is severe. However, you should allow giving the fungicide the required time for it to actually start working. You should be able to see a difference in about a week or two.

It will help to spray healthy hydrangeas with a fungicide to protect them from an incoming infection.

It’s better to keep treating your plants every year to prevent an infection from showing up as the weather changes and becomes wetter.

Anthracnose is a fungus that can create a level of tolerance against certain fungicides. That’s why some gardeners recommend alternating the fungicide being used to prevent tolerance or resistance against chemicals.

best hydrangea Fungicides

The Best Fungicides to Treat Anthracnose on Hydrangea

With fungicides being able to help treat anthracnose on hydrangea, we have created a list of the best fungicides you should know about to keep your hydrangeas healthy.

1. Bonide 811 Copper 4E Fungicide – Best Overall Fungicide

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This reliable fungicide can help control black spots, rust, powdery mildew, and many other diseases. It is designed to be used on fruits, roses, vegetables, herbs, and more. It can be used safely around pets and people.

Item Form: Liquid

Item Weight: 1 pound

Application: Use with a tank sprayer or a hose-end sprayer

Net Contents: 16 FL OZ

The Bonide 811 Copper 4E Fungicide contains copper, allowing it to be safely used on plants to prevent diseases. This product’s GMO-free and organic nature allows it to be administered in organic gardens.


  • Organic and GMO-free
  • Can be used around people and pets
  • Easy to use
  • The odor isn’t too strong

2. Bonide 814 Copper Fungicide – Runner Up Fungicide

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Item Form: Liquid

Item Weight: 2.5 pounds

Application: Use with a tank sprayer or a hose-end sprayer

Net Contents: 32 FL OZ

Organic gardeners can easily use the Bonide 814 Copper Fungicide to keep their organic garden safe from a range of diseases. This product is safe to use even if you have pets and people around. The active ingredient is Copper Octanoate (Copper Soap) for safe and effective application.


  • Non-GMO
  • Approved for organic gardens
  • Safe to be used around pets and people
  • Doesn’t have a very harsh odor

3. Bonide 148 Fungicide Concentrate – Best for Plant Absorption

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Item Form: Liquid

Item Weight: 1 pound

Application: Use with a water-style sprayer, pump-up sprayer, or a dial-style hose-end sprayer

Net Contents: 16 FL OZ

The Bonide Products 148 Infuse Systemic Disease Control Fungicide Concentrate is absorbed into the plant to ensure it isn’t washed away when it rains or when the sprinklers are turned on. This Infuse concentrate can efficiently work for 2-4 weeks against certain illnesses.


  • Can start working from the very first application
  • Encourages color improvement in woody shrubs
  • Assists with turf rooting
  • Easy to use

4. Bonide (BND883) Fungal Disease Control – Best Broad-Spectrum Fungicide

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Item Form: Liquid

Item Weight: 2 pounds

Application: Comes in a spray bottle

Net Contents: 32 FL OZ

The Bonide (BND883) Fungal Disease Control can be used to protect gardens from blights, rusts, scabs, black and brown spots, etc. The active ingredient is Chlorothalonil to ensure this fungicide is a safe broad-spectrum product.


  • A broad-spectrum fungicide
  • Easy to use
  • Doesn’t have a very harsh odor

Wrapping It Up

Many people like having hydrangeas bordering their lawns. They don’t require a lot of care compared to other certain varieties of plants. However, they are vulnerable to fungal infections such as anthracnose. You can keep your hydrangeas safe from anthracnose by using effective fungicides, trimming away infected parts, and ensuring there’s no infected debris near the hydrangeas. We hope our guide about how to treat anthracnose on hydrangea proves to be helpful in your gardening journey.

FAQ – Anthracnose on Hydrangea

Is anthracnose curable?

If an anthracnose infection enters your garden, there are specific steps you can take to cure it. You should immediately trim away infected plant parts. Also, clear the debris from below the plant. Spray the plants with an effective fungicide to prevent further outbreaks of infection.

What fungicide is used for anthracnose?

Fungicides used for anthracnose contain chlorothalonil, copper diammonia diacetate, propiconazole, and the systemic fungicide thiophanate-methyl. Do ensure that you read and properly follow the instructions when spraying plants with a fungicide to safeguard their health throughout the year.

How do you get rid of anthracnose naturally?

There’s no completely natural remedy for you to get rid of anthracnose from plants. However, you can try and save plants by immediately pruning infected parts if an infection does occur. You should also clear away debris from under the plant as spores might be present in said debris. It would also help to water the base of plants instead of the leaves and flowers.
Fungicides are also recommended for preventing anthracnose infection. You can use organic fungicides to keep your garden protected in a somewhat natural manner.

Does anthracnose stay in soil?

Yes, anthracnose is known to stay in the soil. That’s why it’s recommended to remove debris from under your plants. Anthracnose tends to remain inactive during winter by hiding in or on the soil, seeds, and debris. Clearing away infected debris can assist with keeping your plants safe when the warm, wet, or moist weather comes along.

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