There are a number of different organisms that can infect hydrangea plants and sully their beauty. And if you want to know more about growing hydrangea bushes, then check out some of our other guides such as:. See our TOS for more details. Uncredited photos: Shutterstock. Now that she lives near Santa Barbara, California, she is delighted that many of these grow right outside! Fascinated by the childhood discovery that plants make chemicals to defend themselves, Helga embarked on further academic study and obtained two degrees, studying plant diseases as a plant pathology major.
Helga then returned to Cornell to obtain a PhD, studying one of the model systems of plant defense. She transitioned to full-time writing in Oh no! Can you describe the fungus or post a picture of it?
Could it be a virus? Are there any particular symptoms? There are several fungicides used to treat fungal diseases on hydrangea that are systematic. If you will be treating your hydrangeas for a period of time, it would be good to get both fungicides and rotate them, so the fungi do not develop resistance to them. Is there anyway that you can reduce the size of them and try again? If you would like me to, I can delete your previous message.
Helga George, PhD. Your poor plants! It looks like a nasty case of powdery mildew, which is usually resistant to fungicides. You should definitely remove the diseased tissues. Thinning out the plants so they will have better airflow will help them to resist this disease.
And keep disinfecting your pruning shears. There is an organic treatment called neem oil that might help. Hopefully you can save them, and please keep us posted! Is there anything a bit stronger that may work? It sounds like you are doing everything right. There is one other possibility. There are two types of mildew. I thought the disease on your hydrangeas was powdery mildew because there are spores on the top of the leaves. However, it could possibly be downy mildew.
That is actually not a fungus, but it acts like one. Different chemicals are required to kill it. There is a compound called metalaxyl that is sold as Ridomil, Subdue, or Apron that should be available at home improvement stores and should be effective on downy mildew. Try that and see if it works.
Did the other spray help at all? Is there a chance that you could post a picture? Are the leaves folded and stuck together? That could indicate an insect problem.
Or are they crinkled? Viruses can also cause leaves to be distorted. If you could provide more of a description of what is going on, that would help me give you advice. I purchased a hydrangea tree about 3 months ago. I potted it with the idea of bringing it into my home this winter always bring my tree hibiscus in. However, the hydrangea is not doing well. Not sure if I did not give it enough water, but there are spots on the leaves.
Will I make a mistake to bring it into my home? We live in Indiana. It could be stressful for the plant to be inside, since the humidity in houses is typically low, and light is limited.
Do you have the tree on stones in a tray that you can keep wet? Do you mist it? Could you describe the spots? Are they brown, rust-colored, or white? Are they round circles of one color, or do they have rings around them? Would it be possible to upload a picture of the spots? That would make it easier to diagnose them.
Hi Tina, Without a photo, I can only guess. There are several things that could be going on. That can scald the flowers, so they turn brown. The leaves can turn brown from having wilted if the plant is not getting enough water. That could by Botrytis, a fungus that attacks both the flowers and leaves. That can be rust — another fungus. Can you tell me what is killing my hydrangeas? Thank you for posting a picture!
It definitely looks like an infection. It could be fungal or bacterial leaf spot, and the treatments are different. Are you near a county ag extension office by chance? If you provide a leaf, they might be able to help diagnose what organism is responsible. Please help, Helga! We have had an ongoing problem with dieback on certain plants in our yard for years.
The branches wilt and then die back, usually in the fall, and the brown leaves cling after the other leaves drop. It affects both our oakleaf and mophead hydrangeas, our pawpaws, dogwood, and azaleas. We have heavy shade and heavy soil in our yard, and hot summers here in Columbia, SC.
Our yard stays quite dry due to a combination of the heat, a … Read more ». Unfortunately, it sounds like you might have the serious fungal infection Verticillium wilt. The fungus lives in the soil for many years, and there is no way to get rid of it.
You should prune off the infected areas to keep other fungi from growing on them. Unless the problem is so severe that you would have to remove entire sections of the plant.
When watering, be sure to water the base of the plant. That will help keep the leaves dry and further spreading the fungus.
Also, water in the morning so the leaves can dry out during the day and before the temperature drops at night.
To kill the fungus, we recommend using an organic treatment like Neem. Use according to directions on the bottle. But this is natural and normal and, unless the freeze occurs after abnormally high temperatures, it should not harm the hydrangea at all. Hydrangeas grow and bloom best in areas where they can get at least a few freezes in the winter. So, unless one lives in a very cold climate, hydrangeas do not need to be covered when normal winter temperatures are experienced.
If hydrangeas have already started putting out a few leaves or buds in the spring, and a frost is predicted, it would be prudent to cover a hydrangea with a breathable material before the freezing weather this is only practical with small hydrangeas. This action should help to protect the tiny emerging blooms. For more information, here is a helpful article about Protecting Hydrangeas in the Winter.
If you are noticing holes in the leaves, you could have a pest problem. For more information, here is a helpful article about Hydrangea Pests. This is typically caused by not enough water, and a clear signal that the plant needs to be watered soon. For more information, here is a helpful article about Watering Hydrangeas. If you have any questions or concerns, feel free to email us at info plantaddicts.
We also recommend contacting your local extension office for additional help. This page contains affiliate links to products on Amazon. We may receive a commission for purchases made through these links. Use Code: ShopSmallBiz. Search Keyword:. Blog Home. Plant Care. Landscaping Tips. Plant Addicts Anonymous.
Brown Spots on Hydrangea Leaves In a home landscape, brown spots on the leaves are usually caused by a fungus or bacteria. Fungal Leaf Spots on Hydrangea Leaves There are two types of fungal diseases can infect hydrangeas - cercospora leaf spot and anthracnose. Causal agents: Colletotrichum gloeosporioides, Colletotrichum dematium Class: Sordariomycetes In most cases, fungus growing on hydrangea leaves will not kill the plant.
Bacterial Leaf Spots on Hydrangea Leaves Leaf spots on hydrangeas caused by bacteria are from the pathogen Xanthomonas campestris.
How To Treat Brown Spots on Hydrangeas Fungicides can be applied, but most home gardeners do not feel this is a worthwhile option. Hydrangea Leaves Turning Yellow During the growing season the spring or the summer if hydrangea leaves unexpectedly turn yellow and then brown and begin to fall off, a problem with the roots is usually the cause.
How To Treat Yellow Leaves on Hydrangeas If a plant has been allowed to dry out, the first step to recovery is to thoroughly water the entire root ball. Edges of Hydrangea Leaves Turning Brown Hydrangeas growing in a pot or newly planted in the ground have roots that are especially vulnerable to strong applications of fertilizer.
Note: Never fertilize a plant that is not completely healthy! Hydrangea Rust Diagnosing this is relatively easy as hydrangea rust looks different than most other leaf problems.
Causal agent: Pucciniastrum hydrangeae Treating Hydrangea Rust As mentioned above, this disease will spread due to water splashing on the leaves. This is our favorite one below 5. Among them, powdery mildew often makes an appearance in high humidity or when warm days are followed by cool nights. While treatment options are many, prevention is where you should try to focus most of your energy in combating this fungal disease. Powdery mildew causes a white-grey, powdery substance to form on the surface of the leaves.
You may also notice a cottony substance growing on the bottom of the leaves. Small, gray lesions caused by the web of fungus can also appear on the upper part of the leaves. Yellowish-green blotches or leaves turning purple are also signs of this foliage disease. There are several fungi that are responsible for the emergence of powdery mildew including Microsphaera friesii, Oidium hotensiae, Golovinomyces orontii, and Erysiphe poeltii.
Of all the hydrangea varieties grown in the United States, powdery mildew affects big leaf hydrangeas the most. Although the fungus seems to grow primarily on the surface of the leaves, causing a white powder coating, it does sink root-like structures into the leaves to feed off its nutrients, causing lesions and further damage.
What may at first seem like an aesthetical issue that affects the leaves, left untreated, powdery mildew can take over your hydrangea and cause any of the above problems, including complete premature foliage loss. Fungal diseases are easily spread via spores from one plant to the other, and from one branch to the other within the same shrub or plant. They can overwinter on your plants and emerge when conditions are favorable. Unfortunately, environmental conditions that favor the host plant also favor the pathogen too.
High humidity, lack of air circulation and heavy shade are especially hospitable for powdery mildew.
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