Sunlight causes this.
Cold weather can cause citrus leaves to curl and so can water stress. Aphids are another cause.
New leaf growth is caused by the cold soil causing the leaf to curl and fall off producing a new leaf. The cause of the leaf to curl can be from an aphid species or different plant diseases.
The moon.
The scientific name of lemon leaf is Citrus limon.
No, too much water does not make the leaves of a citrus tree curl. Hot sunshine is what makes the leaves curl and twist.
A general answer ( since you did not specify what plant ) is insect damage, drought, or soil is too alkaline.
stunted plants leaf curl up as a cup shape hard leaf midrib yellow leaves
Feeding, for instance aphids; leaf hoppers and rollers, and psyllids. Fungus, for instance nectarines and peaches. Spraying, for instance 2, 4 D drift; or Banvel or Roundup control reactions. Overwatering, for instance tomatoes. Viral, for instance mosaic virus; or squash or tomato yellow leaf curl virus.
The leaf decoction will be great for fragrance.
bacterium
The tomato leaf curl virus is a yellowing and upward curling of leaves on a tomato plant. It is a viral infection that has been transmitted through whiteflies. It will affect fruit production.
Stink bugs