Do I need to prune the curled leaves?

You can prune them if they look very damaged, but it is not strictly necessary. The tree will grow new, healthy leaves once the pests are gone.

Are these bugs harmful to other plants?

Aphids are generalists and can move to other plants in your garden. It is best to treat them early to prevent them from spreading.

European crabapple: curling leaves, causes and fixes

Check these first

Look closely at the undersides of the curled leaves for tiny green or black insects.
Check if the curling happens mostly during the hottest part of the day.
Feel the soil to see if it is dry more than two inches down.

Likely causes

Aphid Infestation
Most likely
How to tell: You will see small, soft bodied insects clustered on the undersides of leaves or on new shoots. The leaves will look distorted or curled inward.
What to do: Spray the affected branches with a strong stream of water to knock the aphids off. If the infestation is heavy, use insecticidal soap or neem oil according to the label instructions.
Heat Stress
Possible
How to tell: Leaves may curl during extreme heat to conserve moisture. The leaves will look wilted but will not have insects on them.
What to do: Ensure you are watering deeply every 7 to 14 days during dry spells. Apply a layer of mulch around the base to keep the roots cool.

Curling leaves on other plants

Find out what's wrong with your european crabapple

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

Worry if the curling is widespread and the new growth is stunted or turning yellow. Minor curling on a few leaves is usually not a threat to the tree.

Stopping it coming back

Encourage natural predators like ladybugs in your garden, as they eat aphids. Keep the tree healthy with proper watering to help it withstand minor pest pressure.

European crabapple: curling leaves? Check yours with a photo

Every plant is a little different. Take a photo of your european crabapple and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Do I need to prune the curled leaves?: You can prune them if they look very damaged, but it is not strictly necessary. The tree will grow new, healthy leaves once the pests are gone.
Are these bugs harmful to other plants?: Aphids are generalists and can move to other plants in your garden. It is best to treat them early to prevent them from spreading.

Guides to these causes

Aphids

Why are my European crabapple leaves curling?

Check these first

Not sure what's wrong with your european crabapple?