Flowering Cherry Tree Problems, Treatment, Prevention & More

During the season of spring, you look forward to seeing your cherry blossoms tree in full bloom.

Who doesn’t want to have a mass explosion of light pink flowers adorning their yard or garden, right?

However, all your excitement can go in vain if your ornamental cherry tree doesn’t bloom or have other growth problems.

Yeah, it will be heartbreaking and make you worried about it. Even I went through such an incident when my cherry blossom tree wasn’t producing flowers properly once.

If you are also having trouble, I can help you in this regard. Today, I will talk about flowering cherry tree problems, how to treat and prevent them, tips on caring for them, and more in detail.

Ornamental Cherry Tree Diseases, Symptoms, Causes, Treatments, & More

If your cherry blossom tree looks sick, you shouldn’t waste time and start to find the reason and solution. And fortunately, it’s not that hard to diagnose the problem.

Cherry blossom tree

The common cherry tree diseases have noticeable symptoms, and you can easily treat them.

To name a few flowering cherry tree problems are rot, spot, and knot. They may also get blight, powdery mildew, and canker.

I have gathered around all the reasons behind their diseases, how to identify them, and what you need to do to prevent them. The diseases I am gonna discuss can be seen in ornamental and/or cultivated cherry trees.

So, keep reading and closely see the pictures to find similarities that your tree has, and you will be able to protect your precious cherry blossom tree.

1. Black Knot

Black knot is a fungal infection that is known for attacking members of the Prunus genus like cherry and plum trees. If you notice distinctive uneven black galls on the branches of your tree, then they are black knots.

Blossom tree suffering black knot

Although this fungus takes time to establish itself, once it does, it effectively strangles or girdles new growth, and if left untreated, it can be devastating to your trees.

Common Varieties That Are Affected By It:

Almost every type of ornamental cherry tree can be attacked by a black knot.

Symptoms:

This disease causes hard, black swellings or knots on the tree that can reach 1-6 inches. If you leave them untreated, then these knots will emerge in numerous locations around the tree and grow in size.

Growing black knot in cherry trees

A velvety, olive-green fungal growth may also hide the knots. And if the knot overgrows, it could cause the diseased branch to bend. Also, infected twigs may stop growing leaves, wilt, or die completely.

Reasons for This Disease:

Apiosporina morbosa is the fungus that causes the black knots in a tree.

During spring and summer, mature knots produce spores. Then these spores are carried to sensitive plants around by rain and wind.

These spores can infect and germinate other new plants at the ideal temperature and wet conditions in just six hours.

And by fall, you will find light brown swellings on the infected branches. In the following spring, the expanding knots develop the olive-green fungal growth.

Hardened black knot

The knots will become harder, rougher, and black as the year continues through summer and fall.

Treatment Guide:

If your tree gets infected by it, prune 3 to 4 inches below the knot during the season when your cherry blossom trees don’t flower.

First, disinfect all your pruning equipment. Then after pruning the twigs, burn or bury them. Otherwise, it might be able to infect nearby healthy trees.

Now, if your tree is severely infected, you should remove it totally.

I won’t suggest fungicides since the Wisconsin Horticulture Division of Extension also doesn’t recommend using them. It’s because this type of treatment is costly and likely to be ineffective.

Prune the branch with black knot

But, when things are still in control, consider treating your tree with an organic fungicide when the green tissue is seen and before and after flowering.

Season of Infection:

This infection occurs from the month of April through June.

Common Risk:

They ruin the beauty of ornamental cherry trees as well as limit the production of fruit.

Prevention Measures:

In case you live in a region where the black knot is found, you have to be cautious while choosing cherry trees.

North Japanese hill cherry

It would be best to select a variety resistant to this disease, such as North Japanese hill cherry, East Asian cherry, and Prunus maackii (commonly known as Manchurian cherry or Amur chokecherry).

2. Brown Rot

Brown rot is another viral cherry tree disease.

Common Varieties That Are Affected By It:

One of the types of cherry trees susceptible to this disease is the kwanzan flowering cherry tree.

Kwanzan flowering cherry tree

Symptoms:

The flowers and leaves of the tree turn brown and start to fall. On twigs, little cankers grow, and gum flows out.

Rotting leaves

Powdery masses of brown-gray spores may be seen on diseased fruits, flowers, or branches when the weather is damp.

Reasons for This Disease:

Monilinia fructicola fungus causes this problem.

If diseased blossoms do not fall off, the virus might spread from the flower to a nearby branch. Twigs then develop cankers, which yield more disease spores.

See also  15 Types of Flowering Cherry Trees

Brown rot thrives in warm, moist environments, and infection can happen in as little as three hours. Insects may act as the medium to spread this disease.

Treatment Guide:

It’s kinda difficult to treat brown rot once it has taken hold. You can begin by pruning the diseased branches and leaves with sanitized shearing tools. Then burn or bury these removals to prevent further spreading.

Pruning tree

Pruning your cherry tree will also help thin it out, allowing for improved airflow. To treat severe infections, you may use a safe organic fungicide.

Season of Infection:

This fungus often attacks the flowering cherry tree when they are in bloom.

Common Risk:

This infection will damage the flower, foliage, and twigs.

Prevention Measures:

A clean growing environment with sufficient airflow and low moisture is the best prevention against brown rot.

One of the essential things for healthy cherry blossom tree growth is pruning.

So, keep pruning them regularly. Pick up and dispose of plant debris around the tree’s base. This will create an environment less prone to fungal spores.

3. Powdery Mildew

Powdery mildew is one of the most common cherry tree diseases that damage both fruit and leaf.

Common Varieties That Are Affected By It:

Powdery mildew mostly affects sweet and sour cherries. Types like the Yoshino cherry blossom tree also get affected by it.

Symptoms:

You will notice light powdery-type spots on the cherry leaves. It is less likely to affect older leaves since they may be immune to it.

Powdery mildew

So, young leaves are more susceptible to it. And the infected leaves can twist, distort, or grow pale. You may also find white fungus on the stem end of the cherry.

Reasons for This Disease:

It is caused by an obligate biotrophic fungus, Podosphaera clandestine.

During fall, tiny structures (chasmothecia) bearing ascospores lie latent in leaves where tree limbs come together. Then, in the rainfall season, these structures discharge the ascospores.

Powdery mildew fungal spread

The wind carries out the ascospores to infect young leaves. And by fall, the fungus goes into its overwintering stage in the chasmothecia to reiterate the cycle next season.

Note that the disease thrives in humid conditions with temperatures between 70 to 80 degrees Fahrenheit.

Treatment Guide:

You can treat this problem with a safe, commercial chemical like a fungicide. You may also opt for a non-chemical solution like a mixture of baking soda and dormant oil to spray on your trees bi-monthly.

Fungicide garden equipment

Alternatively, a combination of water and apple cider vinegar is also very effective against powdery mildew.

Season of Infection:

This disease spreads during late spring and summer.

Prevention Measures:

A healthy growing environment with good air circulation may help to avoid powdery mildew. So, don’t overcrowd cherry trees and maintain enough space while planting several plants.

Also, dispose of rotting plant waste and fallen leaves around their bottom. Lastly, make sure to not overwater them as cherry blossom trees don’t like sitting in a waterlogged place.

4. Cherry Leaf Spot

Cherry leaf spot is formerly known as Coccomyces leaf spot.

Common Varieties That Are Affected By It:

It attacks sweet, tart, and English Morello cherries.

Morello blossoms

Symptoms:

This disease affects cherry tree leaves, with symptoms appearing on leaf petioles and fruit pedicels.

Tiny purple dots will appear on the upper surface of the leaf. These patches will grow to a diameter of about 1/4 inch and turn into a reddish-brown tint.

Cherry leaf purple spot

The centers of the spots might dry up and fall out after six to eight weeks, leaving little holes in the leaf. Before dropping off, older diseased leaves might turn golden yellow.

Older diseased leaf turned into golden yellow

Cherry leaves infected with cherry leaf spots may drop too soon.

Reasons for This Disease:

Blumeriella jaapii fungus is the reason for coccomyces leaf spot disease. This fungus survives the winter on dead cherry leaves on the ground.

Apothecia (fruiting bodies) appear on the leaves in early spring and produce spores. These spores are distributed by rain to healthy leaves, germinating and penetrating the leaf.

Blumeriella jaapii fungus germinating leaves

Following infection, tiny purple spots emerge on the leaves. The undersides of these spots produce more spores (conidia), which show as whitish-pink underleaf lesions.

The conidia are then transferred by rain to other healthy cherry trees, causing further infestations.

Treatment Guide:

Start by removing as many infected leaves as possible from cherry trees affected with cherry leaf spots. Then, using an appropriate fungicide, spray your trees.

You can also use home remedies made with dish soap, baking soda, and water, which are beneficial in treating this problem.

Season of Infection:

Purple spots form on cherry leaves between the end of May and the beginning of June.

Prevention Measures:

Healthy trees are less likely to get fungal diseases, so make sure you feed and water your cherry tree on a regular basis. In addition, regular fungicide spraying can help prevent active new spores from forming.

Watering young tree

Common Risk:

If your ornamental cherry tree is affected, the fruit will have poor taste. Also, dead fruit spurs, weak buds, loss of fruit, and possible tree death may occur.

5. Necrotic Ringspot

All the cultivated types of the genus Prunus including cherries are susceptible to this virus.

Common Varieties That Are Affected By It:

It affects sweet and sour cherries.

Symptoms:

Yellowing and browning of the leaves will show as symptoms. Leaves will establish holes which gives them a shothole outlook. On severely damaged plants, bark splitting and branch dieback occur.

Ringspot

In early summer, leaves may drop, and fruit may distort or mature later than usual.

By the way, this disease spreads relatively slower in sweet cherries than in sour ones. Enations also form on the underside of leaves, which gives them a thick and stiff look.

Reasons for This Disease:

PNRSV (Prunus necrotic ringspot virus) is a plant pathogenic virus that causes ring spot illnesses in cherry blossom trees.

vis spread through pollen

The virus spread through pollen, wood grafting, and seed. And then, the wind and pollinators spread the diseased pollen throughout the entire orchard.

Treatment Guide:

Try treating this by pruning the damaged plant matter and applying fungicide. However, it may not always be effective. Therefore, it would be best if you remove the diseased trees to stop the spreading of this virus to others.

Season of Infection:

They usually get worse in late July or August, when there is a lot of summer stress.

Common Risk:

Necrotic ringspot can harm your tree’s twigs, buds, and leaves, stunting its growth. PNRSV can cause sweet cherry fruit losses of up to 15%.

Prevention Measures:

Necrotic ringspot can spread through pollen, seeds, wind, and wood grafting and is kinda difficult to eradicate. It’s best to choose disease-resistant varieties.

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To avoid the virus getting out of hand, destroy any plants in your garden that may be infected.

6. Cytospora Canker

One of the most destructive and common cherry blossom tree diseases is cytospora canker.

Common Varieties That Are Affected By It:

It destroys sweet and sour cherries.

Symptoms:

The tree branches will grow dark, depressed cankers, which wilt the branch. At the canker’s edge, an amber-colored gum may form.

amber glue coming from tree bark

The canker will ultimately encircle the limb and cause it to die.

Reasons for This Disease:

It is a fungal disease caused by Leucostoma kunzei.

On the canker, black pycnidia and spore-producing structures develop. These black pycnidia will eventually turn white.

Spore masses expel from the pycnidia under humid circumstances. Wind and rain carry the spores, which infect any bark wound.

Sunburn, ancient cankers, or wood-boring insects may have caused these lesions. One thing is that this disease is incapable of infecting healthy, undamaged bark.

If a cherry tree is stressed by drought, potassium deficiency, overcropping, or ringworms, its vulnerability to Cytospora canker rises.

Treatment Guide:

Unfortunately, there is no chemical control that can treat cytospora canker. Removal is the most effective treatment for this illness.

Cytospora canker can be trimmed away, but be cautious about pruning far below the infection location. It can also be removed surgically by cutting cleanly into the bark at the canker margin and carefully removing infected tissue.

Season of Infection:

When the temperature rises above 90 degrees, cytospora canker grows. In the middle to late summer, cankers encircle dead limbs.

Common Risk:

Well-formed cankers will destroy parts of your cherry tree.

Prevention Measures:

Because there is currently no cure for Cytospora canker, the best way to avoid it is to keep cherry trees healthy and vibrant through careful maintenance.

Since the disease enters inside the plants through breaks and wounds, immature plants should be trained early to avoid branch breakage.

Also, you should prune established cherry trees regularly to prevent severe cuts.

7. Silver Leaf

Another fungal disease of flowering cherry trees is silver leaf.

Silver leaf fungus

Common Varieties That Are Affected By It:

It mostly attacks the species of the rose family Rosaceae like Okame, Kwanzan, Yoshino, and many more.

Symptoms:

You will first notice a silver sheen, followed by dying branches. The exact number of affected leaves varies from tree to tree.

The metallic sheen is caused by the epidermis (surface layer) detaching from the rest of the leaf blade. This gap has an effect on light reflection.

Leaf symptoms may not arise year after year, and the silvery leaves may develop brown, dead spots.

These spots may or may not resurface the following year. But, don’t mistake a complete recovery for the absence of symptoms. A brown stain may flow underneath symptomatic leaves on branches.

When examined, a cut portion of dead branches might have dark-stained cores or bracket-shaped fungi.

Reasons for this disease:

The conks are generative structures of the disease-causing fungus. During the wet conditions in autumn, the fungus released from the conks spreads and infects trees with open wounds.

Leaf fungi

Then these fungi live in the water-conducting tissue of branches known as xylem. The dark stain that you will see is because of its presence in the xylem.

The toxin produced by the fungus travels to the leaves and gives the silvery sheen. As the wood decays, the illness develops, resulting in conks on the surface.

Treatment Guide:

To treat silver leaf, begin by removing all affected areas from your tree. Avoid a revival by applying a suitable wound dressing to clipped branches.

Moreover, make sure that there are no infected trees around, and if present, prune those too.

Since the fungus limits water movement in branches, you have to provide enough water to diseased trees.

Season of Infection:

Cold and wet season.

Common Risk:

The silver leaf will cause a slow deterioration in your blossoming cherry tree’s health.

Prevention Measures:

It’s really important to prune your trees properly to avoid silver leaves.

Prune affected branch

Depending on the variety, prune them when they are done flowering. Always make sure that your shears are clean and sterilized to stop spreading the disease.

8. Crown Rot

Crown rot is born from a fungal strain named Phytophthora.

Common Varieties That Are Affected By It:

Any type of cherry tree can be affected by it.

Symptoms:

It’s an aggressive plant menace that attacks and destroys the roots of a flowering cherry tree.

Cherry trees with crown rot may appear to be in decline, but you’ll only know for sure if you investigate the roots of your tree.

Rot is more than likely the culprit if the tissue layer underneath your tree’s top bark is brown or orange rather than green.

Orqange tissue near root indicates rot

Reasons for This Disease:

Excessive watering and damp soil are the most common causes of crown rot.

Treatment Guide:

It is kinda disappointing that once the crown has set in, there is no way to get rid of it. It’s because detecting the disease is hard and is usually too late to stop once it’s identified.

You can try to save your plant by removing the soil around the crown and drying it out only if the damage is not too serious.

Remove damp soil

However, because this illness spreads quickly, it is recommended to kill infected plants.

Prevention measures:

Plant your cherry trees in well-draining soil and water them less frequently to prevent crown rot.

Treatment with fungicides can be helpful, but it is not always effective against this disease.

9. Crown Gall

Another commonly found disease in an ornamental cherry tree is crown gall.

Common Varieties That Are Affected By It:

Woody flowering cherry trees are mostly attacked by it.

Symptoms:

It creates tumor cells that start from the roots and ultimately spread throughout the entire tree. These tumors are normally white, brown, or tanned.

Gall in tree

Reasons for This Disease:

It’s a bacterial disease that lives numerous years in the soil and often spreads from diseased nursery stock. Plants are infected through wounds, and after that, a tiny piece of DNA is transferred into the plant’s DNA that eventually causes the galls.

On young trees, a gall will establish as a soft, spongy, or water-like form on the crown or roots. And in mature trees, the size of the gall ranges from a fraction of an inch to several inches across.

Over time, the galls become hard with a rough, fissured surface. They have irregular growth, so they don’t have any definite growth pattern.

Rough gall

Treatment Guide:

You’ll need to spray a chemical control sprayed across sick areas and infected branches to treat crown gall.

Although this method won’t cure it, it will stop it from spreading. Tumors can also be exposed and removed, which can help your cherry tree heal.

See also  Growing Facts of Cherry Blossom Trees

Prevention measures:

Crown gall progresses in humid conditions and warm temperatures.

Therefore, keep your trees healthy by keeping their crowns dry and planting them in well-draining soil to avoid crown gall. Also, try to prevent hurting or breaking the plants.

10. Gummosis

Gummosis is the cherry plant’s reaction to stress.

Common Varieties That Are Affected By It:

This problem is usually seen in flowering cherry cultivars.

Symptoms:

If you notice any gum seeping from your tree branches, buds, and trunks, it’s gummosis, which signifies that your tree is under some type of stress.

Gum seeping from tree branch

Don’t be surprised cause trees can be stressed too!

Gums will break through the surface and run down the bark.

Reasons for This Disease:

Gumming is caused by several things, including winter injury, mechanical damage, insect damage, or improper growing methods.

In response to these injuries or stresses, a sticky amber oozes from lesions. Canker may become more obvious with time as branches expand or form corky growths on the margins.

Gum oozing from tree wound

Serious damage may result in wilting of leaves and, ultimately, the death of the wood.

Insects such as borers feast under the bark, creating wounds and tunnels on the inner bark. And that’s another reason for branches exuding gum through wounds.

Treatment Guide:

Remove the darkened region of bark as well as a strip of good bark from the tree until a healthy bark margin surrounds the wound.

Once it’s done, let the area dry. You should keep checking the region and repeat the bark trimming if necessary.

Prevention Measures:

Avoid mechanical injuries to your tree by pruning under dry weather conditions. Ensure the tree has a good growing site like well-drained soils and balanced fertilization to boost vigorous growth.

Moreover, practice sanitation by destroying cankered or rotting limbs.

Till now, I mostly talked about fungal and bacterial diseases. Apart from these, pests and insects trouble the tree a lot.

So, let’s gain some knowledge about them.

Problem Caused By Sap-Sucking Insects

Scales, aphids, and spider mites are some common sap-sucking insects that attack cherry blossom trees.

Closeup of spider mite

They eat the phloem sap running throughout the cherry tree, resulting in the leaves wilting, discoloring, and falling from the tree branches.

Generally, these pests are more annoying than a disease.

And when the infestation is large, or the tree’s health is in threat, only then the chemical control measures are necessary.

An effective and organic way of controlling these insects is plant-based insecticides such as neem oil. Mix 2 tablespoons of neem oil with one gallon of water and apply it thoroughly to the infested tree.

Insecticide

Repeat the treatment every 7 to 14 days if needed.

Problem Caused By Chewing And Boring Insects

Many flowering cherry trees are host to many chewing and boring insects like leaf-eating caterpillars, tent caterpillars, and borers.

Tent and leaf-eating caterpillars can be controlled by using the low-toxic bacterial insecticide Bacillus thuringiensis (Bt). It controls the larval stage of insects and is safe to use.

leaf eating caterpillars

It is applicable as a foliar spray utilizing a rate of 4 teaspoons for every gallon of water.

And during mid-May and mid-July, spray the trunk and limbs of the tree with carbaryl insecticide to control boring pests such as peach tree borers.

Before applying the trunk, it is recommended to dilute 1/3 fluid ounce of the chemical with a gallon of water.

By the way, plenty of problems observed on cherry trees aren’t even caused by disease or pests!

Yes. They are usually caused by nonliving factors or abiotic problems or disorders, including excessive rainfall, drought, low sunlight, weather extremes, compacted soil, applying too much fertilizer, planting the tree too deeply, and/or root damage from the tree cultivation around the root.

So, there is no alternative to taking care of your tree properly. I have already provided the prevention method for each type of problem.

Still, I am giving an overall season-to-season monitoring guide for you.

A Complete Guide to Monitoring Your Cherry Blossom Tree

The below table shows you the management procedure for each season.

Season Treatment
Late Winter
If nutrient insufficiency symptoms are present, test the soil for nutrient and pH levels. Sample the roots or root crown for Phytophthora root rot and nematodes if the plants are showing signs of deterioration.

Crowns should be pruned. Remove any dead, dying, diseased (especially canker branches) or competing limbs. Examine and excavate the root collar.
Early Spring
Use oil to keep scales, mites, and aphids away. On trees having a history of leaf spots, shoot blight or black knots; use a fungicide treatment to control them. Water once every two to three weeks.
Mid Spring
Again, if your tree has a history of fungal diseases, apply fungicide. Based on soil test results, use fertilizers and soil treatments to adjust pH as needed.

Borers, scales, caterpillars, mites, and aphids should all be monitored and treated during this time.
Late Spring
Follow the same steps as mid-spring.
Early Summer
Monitor for any diseases and treat as per. Inspect irrigation and soil moisture levels to prevent root disease and moisture stress.

Examine the mulch levels and make any required adjustments. Remove any branches that have become twisted or blighted. Water the tree once or twice when the top two-inch of the soil is dry.
Mid Summer
Follow the same steps as early summer.
Late Summer
Follow the same steps as early summer.
Early Fall
Monitor and treat for insects and diseases. Ensure the soil has enough moisture before winter arrives to avoid harm.

To limit the danger of illness and rodent harm, remove any mulch from stems. Apply a soil pesticide treatment to reduce pest problems the following year. Water once every two to three weeks.

Anyway, I think you gained enough knowledge regarding today’s topic. Hence, let’s move on to the conclusion.

Conclusion

Hopefully, my write-up on flowering cherry tree problems will help you protect yours.

Don’t forget to monitor them regularly. Lastly, I hope your cherry tree keeps blooming every year and adorn your garden like a beautiful paradise.

Have a great time….

Frequently Asked Questions:

Most varieties of flowering cherry trees have a lifespan of 30 to 40 years. But, with proper maintenance, they can live longer.

Look for brittle, dry limbs and fragile, disintegrating tree wood.

Even in the winter, dead cherry trees will rot from the inside out, and the wood will give a visible indicator that the tree is dead.