I have a potted Meyer lemon tree and my parents currently have a large lemon tree in their backyard. Every now and then, one of the trees starts dropping more leaves than usual. To help resolve this, I did some research. Here’s what I found.
Lemon trees drop leaves from over or under-watering, extreme temperatures, transplant shock, pests, and diseases. However, issues with watering and temperatures are the most common. To prevent leaves from dropping, only water lemon trees when the first 2-4 inches of soil gets dry and avoid temperatures below 27ºF.
So, lemon trees drop their leaves for several reasons, but how do we know which issue is causing it, and what are some steps we can take to fix it?
Do Lemon Trees Normally Lose Their Leaves?
It’s normal for lemon trees to lose around 10% of their leaves at any given time. This can include leaves that curl, wilt, yellow, brown, and finally—fall off. If lemon trees are losing more than 10% of their leaves, they’re likely stressed from issues such as watering, weather, or disease.
As a general rule, if a lemon tree is maintaining 90% or more of its leaves, it should be relatively healthy. Of course, this is just an estimate and you should consider checking your lemon tree’s soil, leaves, and fruit every 1-2 weeks.
If you do see over 10% of its leaves dropping, checking the tree and its environment will help identify the issue and, hopefully, save the tree.
Do Lemon Trees Lose Their Leaves in the Winter?
Lemon trees are evergreen trees, so they don’t shed their leaves in the winter like deciduous trees. Whether summer, winter, or any other time of year, if a lemon tree starts dropping its leaves, it likely has an issue that needs to be addressed.
So, now that we know it’s not normal for lemon trees to lose more than 10% of their leaves, no matter the season, what are the main reasons why lemon trees drop their leaves?
Reasons Why Lemon Trees Drop Their Leaves
Over or Under-Watering
Issues with watering are the most common reason why lemon trees drop their leaves prematurely. While under-watering can cause the tree to experience drought stress, over-watering can lead to root rot. Both of these cases lead to leaf drop. For best results, only water when the top 2-4 inches of soil is dry.
Lemon trees are native to the tropics, so they prefer warm weather, lots of rain, and well-draining soil (which is common for tropical, sandy soils). If they get too little or too much water, they’ll become stressed and die.
And one of the first parts that are shed from a dying lemon tree? The leaves.
The best way to water lemon trees is to only water when the first 2-4 inches of soil becomes dry. A good way to check this is by pushing a finger into the soil, up to the second knuckle. If the soil is sopping wet 1 or more hours after watering, it likely needs to be amended for better drainage.
If you do find that your lemon tree’s soil has poor drainage (common for soils that are high in clay), you can amend it by adding sand and compost on top of the soil. Over time, these materials will be naturally worked into the soil, breaking up the larger clumps and promoting better drainage.
For planted lemon trees with poor drainage, you can also relocate them to ground that’s more elevated, such as a mound or raised bed. Even a slight elevation will let gravity assist in pulling more water out of the soil.
For potted lemon trees with poor drainage, you can either drill more holes into the pot or repot the tree with fresh soil. If you’d like more information about potting soil for lemon trees, check out my recent post: Create Amazing Homemade Potting Soil for Your Citrus Tree.
Also, consider starting composting and mulching if you haven’t already.
Compost not only provides quality nutrients but improves the soil’s richness. Every 1% increase in the soil’s richness can hold an additional 20,000 gallons of water per acre.
Mulch dramatically reduces evaporation from the soil and helps the tree become more self-sufficient when it comes to watering. It also protects the soil from eroding along with beneficial soil life. Some good mulches to use for lemon trees are grass clippings, leaves, bark, straw, and pine needles.
For best results, apply 2 inches of compost every 1-2 months and 2 inches of mulch every 3-6 months. Keep the compost and mulch at least 3 inches from the trunk to prevent mold and disease from spreading. Lastly, make sure to address any drainage issues first before composting and mulching.
Lemon trees prefer temperatures between 27ºF to 100ºF and will start to drop leaves outside of this range. Frost and cold stress can kill the tree, starting with the leaves and branches. On the other hand, the heat won’t stress the tree unless the soil becomes dry or the leaves’ surfaces burns.
As tropical plants, lemon trees generally can’t handle the cold too much. While lemon trees are typically hardier than other citrus trees, temperatures in the low 20s can start to kill the tree.
However, lemon trees can handle quite a bit of heat as long as they have enough water. This is a big reason why they do so well in climates such as Florida. Although, in hot and dry climates like California, Nevada, Arizona, New Mexico, and part of Texas, they’ll likely need some extra water and shade.
Cold Weather Tips for Lemon Trees
In general, it is recommended citrus trees be protected when the temperatures is expected to go below 27 degrees for an extended period.Dr. William Johnson, Extension Horticulturist, Galveston County Texas AgriLife Extension Service
If you’re growing lemon trees outside of USDA zones 9-11, here are some tips that might help to keep your lemon tree alive in the winter.
- Plant in a south-facing direction. This will provide the maximum amount of sunlight and warmth.
- Plant along a south-facing wall. The wall will reflect sunlight and heat onto the tree, even into the night.
- Insulate the tree in times of frost. You can use sheets or cardboard as insulators.
- Move potted lemon trees indoors or into the greenhouse during frost.
Hot and Dry Weather Tips for Lemon Trees
While it’s more common for lemon trees to be affected by frost, they can still get overheated, especially if their soil dries out.
Here are some tips to help lemon trees survive hot and dry weather:
- Compost and mulching are a MUST in dry weather. While these are great practices to use in general, they’re especially beneficial in hot and dry weather. For more information, reference the above section on watering.
- Shade the tree and soil from some of the hot afternoon sun. The morning sun is much cooler, so shading for a period in the afternoon can go a long way. You can use an umbrella, shade sail, or other trees.
If you’ve recently relocated or repotted your lemon tree, and its leaves are falling off, it’s most likely affected by transplant shock. Lemon trees can become stressed from damage from moving and having to establish a new root system. For best results, avoid damaging the rootball and plant quickly.
It can take a while for lemon trees to recover from transplant shock—sometimes up to one year. Because of this, it’s best not to transplant lemon trees unless it’s necessary. For example, potted lemon trees should be repotted every 3-5 years to avoid the tree from getting root-bound.
While transplanting trees can be tricky, there are some ways you can minimize the stress. For instance, I recently repotted my avocado tree, and luckily—it recovered almost immediately.
If you’d like, here are some steps that I commonly use to prevent transplant shock with my plants:
- Have the new ground (or pot) prepared
- Remove as much of the tree’s current topsoil as possible, without damaging the shallow roots
- Grab the base of the tree’s trunk and wiggle lightly
- Using your other hand, scoop up and support the rootball
- Lightly place the tree in the new ground (or pot) and fill it in
- Make sure the soil is at the same level on the trunk as before
- Apply 1-2 inches of compost and mulch to the top of the soil
- Water generously and add more soil as needed
While it’s not normal for lemon trees to shed their leaves, it can happen if they’re stressed. Typically, this is from improper watering, poor weather, transplant shock, pests, and disease.
Lemon trees commonly live up to 50-60 years, so if your tree is around this age, it might explain the dropping leaves.
Generally, a good way to tell if your lemon tree has a pest or disease is by inspecting the leaves, branches, and trunk. If you see any spotted leaves, bugs under the leaves, or the branches and trunk cracked, the tree could be infected. If you’d like a great resource to identify citrus diseases, check out this post from the University of California Agriculture and Natural Resources.
For more information on why lemon trees get yellow leaves, you can check out my recent post: How To Fix Yellow Leaves on Your Lemon Tree.
If you’ve tried everything and your lemon tree is still declining, then consider consulting your local professional orchard, nursery, or county extension office. They’ll have specific and regional information for what could be affecting your lemon tree.