The leaves of an apple tree are generally flat and happy, so when they start curling, it is pretty noticeable and can make you worry about your tree’s health. There are many causes of this problem, and certain reasons need to be dealt with right away, or your plant could die. So, why do apple tree leaves curl?
There are various causes of the leaves of apple trees curling, including overwatering or underwatering the tree, a nutrient deficiency in the soil, diseases, or pests attacking your tree. These problems can be fixed if you identify them in time before they cause the tree to die.
Having your apple tree’s leaves curl can be a concerning thing, but it is not always your fault, and generally, the problem can be fixed. Let us see how to fix the curls in your apple tree’s leaves and how to help prevent this problem in the future.
Why Apple Tree Leaves Curl
The leaves of Apple Trees can begin to curl due to several stresses that can occur in their environment. These stresses can be several things, some of which you may not even think about as they are less common, making diagnosing the problem pretty difficult at times.
The number of causes for this problem is not vast, but they can be difficult to identify as many of them show similar symptoms. Here are the possible causes of your leaves curling:
- Improper watering of your apple tree
- Diseases attacking your apple tree
- Pests attacking your apple tree
- Lack of nutrients in the apple tree’s soil
The first step at diagnosing the cause of the leaves curling is to take a good look at your apple tree and how it’s behaving apart from its leaves curling. Are there any other unusual signs that you did not notice before?
Let’s go through these causes more in-depth and what other symptoms each cause has, so you can identify the problem faster and fix it before there are any long-lasting effects on your apple tree.
1 – Improper Watering of the Apple Tree
Improper watering practices can cause your apple tree’s leaves to start curling; this is both underwatering and overwatering your apple tree. Dehydration is a very common cause of leaves curling in apple trees.
Dehydration is more likely to occur if you reside in hot climates as the evaporation rate of the water in the soil is increased in hot weather. However, it can still happen if you underwater your apple tree regularly.
If your apple tree is dehydrated, the leaves will begin to curl from the tips of the leaves down, and then the leaves will start to wither and dry out.
Young apple trees and potted apple trees are more susceptible to dehydration than fully grown trees with a mature and branched root system. To determine whether it’s a lack of water causing your apple tree’s leaves to curl, you can do the finger test.
This is where you stick a finger into the soil at the base of your apple tree, and if you feel that the soil is dry more than 3 inches deep, this could indicate a lack of water.
Overwatering can also cause the leaves of your apple tree to curl. If you overwater your apple tree and your tree is not in well-draining soil, this could be the reason for the leaves curling.
When you overwater your apple tree, the soil becomes fully saturated with water and starts to suffocate the roots of the tree. This affects the absorption of water and other key nutrients that the tree needs to survive.
The leaves are then starved of these key nutrients and water, and they are in the sun and become dehydrated, so they begin to curl. This does mean that the symptoms of overwatering your apple tree are very similar to what you would see if you underwater your tree.
However, there is one tell-tale symptom of overwatering your tree that will not happen if your tree is underwatered; this is the discoloration of the leaves. The apple tree leaves will begin to turn yellow and then brown if the tree is overwatered.
You can also check the soil of your apple tree to ensure this is the cause of the problem. You can use the finger test for this too. Stick your finger about 3 inches deep into the soil and if the soil is extremely wet, then overwatering is most likely the cause of the leaves curling.
To ensure that your apple tree recovers from improper watering and that you never face this problem again, you need to water your apple trees correctly. If your apple tree is suffering because it was overwatered, you need to stop watering the tree and let the soil dry out.
If the apple tree is suffering from being underwatered, you need to begin watering your tree more frequently; however, do not do this too quickly as you can cause the tree to go into shock. Slowly reintroduce more water to your tree over a week or two, and then go back to watering your tree correctly, on a regular schedule.
Using the finger test is the best way to determine if your apple tree needs to be watered or not, and this will help you create a watering schedule for your tree as you can see how long it take for the soil to dry out.
Using the finger test, if the ground is dry 3 inches below the surface, you need to water your tree. Do not let the soil dry further than 3 inches below the surface, or this could cause your tree to suffer from drought conditions.
2 – Diseases Attacking the Apple Tree
Apple trees can also suffer from bacterial and fungal diseases that can cause the tree’s leaves to curl and become discolored. Unfortunately, many diseases can affect apple trees, so not all of them will be listed here. However, we will go through the most likely diseases you will face with your apple tree.
One fungal disease that you may find on your tree is powdery mildew, which presents itself as a white powder on your tree’s leaves. If you do not pick up on the disease, it can cause the leaves to curl and then shrivel up and die.
Another fungal disease that may affect your apple tree is apple scab. This fungus thrives in moist conditions and will create dark brown or yellow speckles on the leaves of your apple tree. The leaves will then begin to curl and turn yellow; they will die and fall off the tree.
A bacterial disease that you may encounter with your apple tree is called fire blight. This will cause the leaves of your apple tree to have a scorched appearance as they begin to curl and dry out and then eventually fall off the tree. This disease will affect more than just the tree’s leaves and needs to be dealt with as soon as you identify it.
With fungal and bacterial diseases, prevention is as important as curing the disease once the tree is infected. So, to cure your apple tree of powdery mildew, you need to take a hose with good water pressure and spray off the powder from the leaves, and then if there is any left, spray a fungicide on the leaves to kill the remaining fungus.
If your apple tree is suffering from apple scab, you will need to spray the affected areas with fungicide as soon as you have identified the disease. Then with fire blight, you will need a more intensive treatment option.
First, you will need to prune all the withered branches of the tree and then speak to your local garden store or service about using a Bordeaux or copper mixture to treat the disease.
The best way to prevent both fungal diseases is by keeping good orchard hygiene and air circulation with your apple trees. You need to prune your trees to allow for good air circulation and ensure that you pick up any fallen fruits and leaves from around the tree and throw them in the trash.
To help prevent fire blight, you need to remember that this bacteria lives in the tree’s bark through the winter months and will generally only present itself in the spring. So, in the spring, you need to check your apple trees for any oozing spots from the bark and spray them with one of the mixtures mentioned above.
3 – Pests Attacking the Apple Tree
Pests are a problem for apple tree owners as they can cause the tree’s leaves to curl, but they can also bring about the death of your tree. Certain pests are more likely to infest your apple tree than others, and these include aphids, midges, and leaf rollers.
Aphids are small, green, or white insects that you will find gathering on the bottom of the leaves of your apple tree. These bugs will bite into the leaves of your apple tree and suck out the sap from the cells, which causes the leaves to curl. This will also create a brown mark on the leaves where they were bitten.
Midges are small flies that will lay their eggs on the leaves of young apple trees. In the spring months, the eggs will hatch, and the larvae will eat on the leaves, making them curl around the larvae. The leaves will generally turn brown and then fall off the tree.
Leaf rollers do not feed on the leaves of your apple tree but rather use them to make their cocoons by using a silk thread to roll up the leaves to create a home for them while they are in their larvae stage.
Dealing with pests can be an annoying task as the infestation can grow overnight and spread between all your plants. If you are lucky, the infestation may attract the natural predators of the pests like ladybugs, and the problem will fix itself without you intervening.
However, if the infestation is pretty big, you will need to step in to save your apple trees. If you are dealing with aphids, you can spray the bugs off your trees using a hose with high water pressure. Then, to help treat and prevent the insects from returning, you can spray your trees with an insecticidal soap or a diluted neem oil spray.
If you have a midge infestation, you need to prune off the infected areas and destroy them. Spraying an insecticide will not work as the larvae will be protected by the leaves that are curled around them.
If you have leaf rollers, you can start by spraying them off your trees with a high water pressure hose, ensuring you spray into the curled leaves to spray the larvae out. Then you can spray your apple tree’s leaves with an insecticidal soap or neem oil spray.
4 – Lack of Nutrients in the Apple Tree’s Soil
If your apple tree does not have sufficient nutrients in the soil, this can cause the leaves to curl and then fall off the plant and die.
Apple trees require a large amount of nutrients, especially when it is growing fruit. If the tree is not fed enough throughout this time and prepares to produce its fruit next year, this can lead to deformed leaves.
Apple trees need to be fertilized regularly to ensure that they have enough nutrients and minerals to grow correctly. You also need to keep an eye on the soil’s pH level, as this will affect the effectiveness of your apple tree’s absorption of nutrients.
The pH level is the soil for your apple trees needs to be more alkaline at 6.5 for your trees to remain healthy. Once the pH level is correct, you can then fertilize your apple trees with a good-quality fertilizer.
The best fertilizer is a good multi-purpose tree fertilizer with a balanced NPK formula to provide your apple tree with all the nutrients it needs to thrive and produce delicious fruit.
If you are using normal fertilizer, you should fertilize your tree once a month during its active growing season. However, if you are fertilizing using pellets, you only need to fertilize once in the early spring and then once in the mid-summer.
There are many causes that you can look into if your apple tree’s leaves begin to curl. Some of the reasons are a big cause for concern as they can kill your apple tree, so you need to identify the problem as soon as possible and then treat it fast.
To find the right diagnosis for your tree, go through the above list one at a time and see which causes are relevant to your tree, and then fix the problem. Good luck with your apple tree!
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.