Lemon trees are evergreen, but they still replace older leaves. Occasional leaf loss can be normal; rapid or extensive loss, especially with wilt, dieback or poor growth, deserves investigation. A lemon tree should not be expected to become completely bare every winter like a deciduous tree.
Begin with what changed: watering, light, temperature, location, pot size or root conditions. Leaf drop is a symptom, not a diagnosis, and adding fertilizer before identifying the cause can complicate the problem.
Check the pattern and recent history
Note whether the falling leaves are older or young, green or yellow, and whether the whole canopy or one section is affected. Photograph the plant over several days so you can tell whether the problem is continuing rather than relying on one pile of fallen leaves.
Record recent moves indoors or outdoors, cold events, heat, missed watering, repotting and nearby chemical use. A tree in the ground faces different conditions from a container moved between a patio and a heated room.
UC IPM identifies citrus as evergreen trees and shrubs. Do not confuse leaf loss with the normal shedding of some small fruit after flowering; those are different processes.
Inspect moisture and drainage first
Check moisture within the root zone rather than watering automatically because leaves are falling. A pot can have a dry surface and remain wet lower down, while water running quickly from the bottom can sometimes bypass a dry root ball.
Make sure drainage outlets are open and empty water trapped in an outer pot or saucer. Conversely, correct repeated drying during active growth. The appropriate frequency changes with weather, plant size, growing medium and whether the plant is indoors.
Maryland Extension’s container-citrus guide discusses watering and indoor conditions. Use it as guidance for comparable container situations, not a fixed irrigation schedule for every outdoor lemon orchard.
If the mix stays wet unusually long, roots smell unpleasant or the plant continues to decline, seek help before repeatedly repotting or adding more water. Root problems are not resolved by improving airflow around the leaves alone.
Review light and temperature changes
A bright-looking room may provide much less usable light than the plant had outdoors. Place indoor citrus where it receives suitable light, with supplemental growing light if needed. Avoid abrupt changes and protect it from cold drafts or hot, dry air blowing directly from a heater.
When moving outdoors, acclimate the plant rather than putting indoor-grown foliage immediately into intense sun. Minnesota Extension’s indoor-citrus guidance provides a useful starting point for seasonal container care. Local climate determines when an outdoor move is appropriate.
Cold injury and severe heat can both cause problems. A protected position is helpful only if its light, drainage and temperature actually meet the plant’s needs; moving a stressed tree into a dark room is not a general remedy.
Inspect for pests and other damage
Examine leaf undersides, stems and growing tips for insects, webbing, sticky deposits or unusual lesions. Record what you find instead of choosing a pesticide from leaf drop alone. UC IPM’s citrus leaf and twig guide illustrates several disorders that require different responses.
If treatment is needed, use a product labeled for edible citrus and the actual setting, including indoor use when relevant. Follow harvest and other restrictions. A product suitable for ornamental houseplants is not automatically appropriate for a fruiting lemon.
Support recovery without forcing it
Correct the identified conditions and monitor new growth. Feed according to the plant’s active growth, regional citrus guidance and the product label; more fertilizer is not a reliable cure for damaged roots or insufficient light. Avoid removing large amounts of healthy canopy simply because some leaves have fallen.
Recovery depends on the remaining healthy stems and roots and on the cause of stress. There is no guaranteed deadline for replacement leaves. Persistent decline, widespread dieback or suspected disease calls for a local extension or citrus specialist’s diagnosis, with the tree’s history and photographs supplied.
