Why do tree leaves curl?

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The most common reason why many people love taking care of plants and trees aside from they offer benefits such as cleaner air is that they are transparent. In fact, when people who are into gardening are asked why they are interested in anything related to horticulture, most of them say that the reason why they prefer to deal with plant life compared to humans is that they are honest. 

When plants are in a good shape, you can usually tell immediately by observing their healthy leaves and lush color. When they are not doing well, however, it will often show by having a pale color, bite marks from insects, and falling leaves. 

One of the things that show your trees or plants are having some issues or problems is when their leaves are curling. 

Why do the leaves on a tree “curl”?

 

 

 

 

 

When the leaves on a plant or tree curl, this usually indicates a bigger problem. There can be a lot of reasons why the leaves on a tree curl, such as pests, herbicides, or not enough nutrients. Depending on the reason why the curling is happening in the first place, the solution can be simple or may take more time and effort for the incident to be stopped.

In the case where leaves “curl”, this would mean that instead of the leaves being what they regularly look like, some parts of the leaf may be curved or look permed instead. This can be deduced by having a thorough plant observation and inspection. 

The curling of the leaves can appear upward or downward, which can also be an indication of why it is happening. When combined with other signs that are currently present in your tree, it would be possible to identify the culprit and see if there is anything you can do to return the leaves to their original appearance. 

Common causes why tree leaves are curling

Here are the most common reasons why leaves curl in a particular position and what can be done about it. 

When the leaves of your tree are curling upwards or inwards, it may be due to:

  1. Pests 

Indicators: When a tree is damaged due to insects and pests, the curling of leaves may be observed upon inspection. Other signs of a pest and insect infestation are wilting, yellowish spots, molds, streaking, crumbling, and many more, depending on the specific cause. 

Some of the pests or insects that can cause curling leaves:

Thrips – An insect that looks similar to a thread and pierces the plant to get the sap on some shade trees, resulting in the wilting of the leaves and white patches to appear. When thrips are the culprit, the leaves may also appear to have bronze or silver streaks. 

Spider mites – Are arachnids that inflict damage on the plant by sucking out the sap and nutrients in it. When spider mites are the culprit, it is possible for the tree to have webbings. 

Aphids – A pest that can be in any color, and is often pear-shaped. Aphids also suck out the fluids from the tree and can be found on the underside of a leaf. When aphids are the culprit, it is possible for the leaves to turn yellowish and for black mold to appear.

What you should do: The treatment will vary depending on what insect or pest specifically caused the leaves to curl. Insect-killing soap sprays are often very effective and may solve the problem quickly. 

  1. Herbicides

Indicators: Most plants and trees are very sensitive to herbicides. When trees make contact with herbicides, though intended or not, their leaves will be affected, possibly causing them to curl and even wilt. Herbicides that cause this to happen are usually the variants that contain chemicals such as 2,4-D and glyphosate. Aside from curling, it can result in leaf loss, leaves turning yellow or brown, and branches being weak and easy to break. 

What you should do: Before applying herbicide to your grass or plant, make sure that you have read the instructions so that you can be sure that you are applying it correctly. By doing this, you can avoid transferring harmful chemicals to your tree. 

  1. Not enough nitrogen

Indicators: If your tree is not able to get the nitrogen supply that it needs, it can be severely affected, causing the leaves to curl, turn yellow, and for the tree to stop growing and be stunted. 

What you should do: Apply a fertilizer that has a formula rich in nitrogen.

  1. Dehydration

Indicators: Dehydration and heat shock in trees can be the cause of curling leaves that will eventually turn brown and fall, which can result in its death, once nothing is done for the tree to be hydrated. 

What you should do: If your tree is still young and is still placed in a pot, you can move it once the heat is too much. If your tree is already planted, make sure to water it regularly, especially during hot and dry summers. 

  1. Disease

Indicators: There are many diseases, such as powdery mildew, that can cause damage to your tree, causing its leaves to be riddled with spores, resulting in them appearing curled and blistered.

What you should do: Ask your arborist and do your research about a garden spray that can be applied to your tree. There are several sprays available that are proven to stop the spores from growing and spreading on the tree. 

When the leaves of your tree are curling downwards, it may be due to:

Overwatering 

Indicators: When your tree is overwatered, it can cause the leaves to droop and curl, and the branches and stems will eventually get too heavy and may break.

What you should do: Stop watering your tree in the meantime to let it absorb the moisture. Make sure to not water your tree too much. Observe how much water your tree needs in order to be healthy. 

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