One year, our orange tree started losing a lot of its leaves. We weren’t yet sure why, but it was just about autumn, so we thought it was a seasonal thing. The only problem is, our citrus trees never before shed their leaves in the fall and winter. So, is this normal? Do citrus tree leaves stay green year-round, or do they lose their leaves in the fall and winter?
Citrus trees are evergreen, which means they normally keep green leaves all year and don’t shed them in the fall and winter. Other fruit trees that do shed leaves in the fall are called deciduous trees. If your citrus tree is losing leaves, it’s likely stressed by a change in watering, nutrients, or temperature.
So while citrus trees are supposed to stay green all year, what are some reasons why citrus trees lose leaves and what can you do about it? Let’s take a closer look.
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Reasons Why Citrus Trees Lose Leaves
Citrus trees can lose leaves for a variety of different reasons, but generally, it’s from a type of stress. The good news is that these conditions are reversible if you catch them early enough. Let’s take a look at some of the causes of citrus leaf drop.
Lack of Nutrients
One of the most common reasons why citrus trees lose leaves is due to a lack of nutrients. Citrus trees are heavy nitrogen feeders, so they’ll need a lot in their soil to grow their canopy sufficiently.
This is why their NPK is suggested to have double the nitrogen to phosphorus and potassium.
Of course, citrus trees also need some phosphorus and potassium to maintain healthy blossoms and the overall health of the tree, but nitrogen is definitely the primary nutrient.
To see more about Down to Earth, along with my other recommendations for citrus tree fertilizer, check out my organic citrus tree fertilizer post.
Usually, citrus trees only need to be fertilized once or twice per growing season. This is typically in the spring but can vary depending on the variety.
Lastly, it’s also important to main a proper pH in the soil as one that’s too acidic or too alkaline can disrupt the citrus tree’s ability to absorb nutrients from the soil. The ideal soil pH for citrus trees is between 5.5-6.5.
If you’re looking for natural ways to slightly alter the pH of the soil, you can add wood ash for alkalinity or coffee grounds to make it more acidic.
There are some ways you can measure the pH of soil at home, but it can be a bit of a learning curve. I’d suggest getting a small pH meter you can stick in the soil. They only run a few dollars on Amazon, so it can be well worth the price. To see the pH meter I use, along with some other recommended tools, you can visit my recommended tools for citrus trees page.
Improper watering is one of the other most common reasons why citrus trees lose leaves and die, so it’s important to learn how to do it right. Properly watering citrus trees takes some practice, but it’s well worth the effort.
If you aren’t familiar, deep watering is the practice of watering plants less often but for longer durations.
There are several benefits of deep watering:
- The tree grows deeper roots
- The roots hold more water in the ground
- Less water is evaporated
- Water is shared with other nearby plants
The problem with light and shallow watering are that the citrus tree will also only grow shallow roots. After all, why would the tree spend the energy growing deep roots if all of the moisture is in the top 2-4 inches of soil? It’s just going to simply spread its roots farther to capture more water, instead of going deeper.
Shallow watering and shallow roots pose several problems:
- The tree is highly dependent on frequent watering
- The roots won’t anchor the tree as well
- When heat or drought occurs, it dries out the shallow soil, and therefore, the shallow roots
- Much of the surface water is lost through evaporation
- Little water is held by the shallow roots in the soil, so other nearby plants also dry up faster
So, when a citrus tree is deep watered and trained to grow deep roots, a drought might dry out the top several inches of soil, but the tree can still access the water several feet below the soil. The result is that the tree is more self-sufficient and can survive more extreme elements with little to no help.
It sounds crazy, but it’s true.
The moisture retention in the soil and the water held deeper in the ground will be so efficient that infrequent rains will be more than enough to keep the citrus trees properly watered indefinitely.
So, while deep watering isn’t a necessity, it’s definitely a great practice to get into and can ensure you don’t have to worry about your citrus tree losing its leaves to improper watering.
If your citrus tree is losing leaves in the fall or winter, then it could be due to frost and the cooling temperatures.
Citrus trees prefer temperatures between 35-95ºF, so if its climate is consistently below this, then it’s a highly likely reason why the tree’s leaves might be dropping.
To protect planted citrus trees from frost, it’s best to cover them with sheets or other insulating materials. Additionally, protecting them from wind chill will go a long way. You can plant citrus trees behind natural structures such as existing buildings or large trees to help break the wind and lessen the wind chill.
For potted citrus trees, you can protect them from frost by covering them or by bringing them inside until the extremely cold temperatures are over. Sometimes this can last several months.
For best results, keep potted citrus trees near windows for maximum sunlight, and away from central heating units to avoid the shock from the dry and hot air.
Heat or Drought
Citrus trees are originally from subtropical and tropical regions, which are places that typically don’t get extreme drought or heat. The times they do get heat, the citrus trees are often shaded by other, larger tropical trees. But what happens in places that aren’t native to citrus trees? What are the effects of heat or drought?
Extreme heat or drought can quickly dry out the first 2-4 inches of soil, preventing the water stored in the citrus tree root from sending moisture up to cool the leaves off. This causes them to turn yellow and drop.
So, it’s fairly safe to say that citrus trees, especially those with shallow roots, aren’t designed to handle drought all that well.
At least with deeper roots, citrus trees can access deeper water tables which send water to the leaves and fruit, keeping them sufficiently cool during extremely hot days.
The best defense against hot days and drought is to practice deep watering and mulching your citrus trees. Mulch, such as leaves, grass clippings, and other garden scraps, are incredibly effective at retaining water in the soil and preventing the sun from baking the soil dry.
Additionally, the mulch breaks down over time and provides a good supply of nutrients in the soil. Meaning you don’t have to fertilize your trees as often, if ever.
The wind has a similar effect as drought since too much can dry out leaves and soil quickly. Additionally, if your citrus tree has shallow roots, the wind can easily topple it. Once a citrus tree has fallen over, it will likely die from the shock of its exposed roots.
The best way to prevent your citrus tree from suffering from wind damage is to create natural wind barriers and encourage deep roots to anchor the tree. As mentioned, deep rooting is best promoted through deep watering.
Providing natural barriers from wind can be as simple as using your house or wall as a barricade, or planting taller and stronger trees as a windbreaker.
If you have to relocate your citrus tree, or if you have to repot it, it will likely go through transplant shock. While there are ways to minimize the effects of the shock, it can still cause leaves to fall off, at least in the beginning.
For best results, transplant your citrus tree as few times as you can. Planted trees shouldn’t need to be transplanted unless something extreme such as disease is occurring. For potted citrus trees, transplanting is much more common.
For example, potted citrus trees need to be repotted at least every 3-5 years. This usually means increasing the size of the pot and possibly even trimming or pruning the tree’s roots.
Here are some more tips to reduce the effects of transplant shock.
- Transplant in early spring, or before the growing season
- Avoid touching the root ball as much as possible
- Deeply water the tree after transplanting
- Only transplant when you have to
With some practice and a guided-hand, you can reduce the effects of transplanting and prevent the citrus tree from losing its leaves.
Pests or Disease
There are some pests or diseases that can infiltrate citrus trees, especially in the warmer and humid seasons. Normally, the leaves are a major point of infection.
Bacterial and fungal diseases will normally create yellow or brown spots on citrus leaves. Other times, the bark on the trunk and branches can crack.
If you do find evidence of disease, then the best thing to do is to prune the infected areas and apply a fungicide (ideally organic) to remedy the fungus.
For pests that are on or under the citrus leaves, such as aphids, then blasting them with a jet of water from the hose, or applying neem oil will help get rid of them.
We once had aphids on our kaffir lime tree, and spraying water on the leaves was enough to get rid of them. However, I’ve also heard that a natural predator to aphids are ladybugs, which you can get at most gardening stores. We’ll try this out next time we come across aphids.
However, if your citrus tree is simply losing leaves, and there aren’t any signs of disease or pests, then it’s likely one of the other forms of environmental stress listed above.
Do Citrus Tree Leaves Grow Back?
Citrus trees can grow leaves back in at least 2-3 weeks. However, if the tree is still undergoing stress, it will likely lose more leaves before growing new ones back. For best results, identify and resolve the stressor as soon as possible to prevent further leaf loss and provide a high nitrogen fertilizer.
Also, make sure to check for signs of any disease, pests, or drought.
If the citrus tree has bark that’s splitting or spotted leaves, then it’s likely disease. If there are small bugs under the leaves (like aphids), then that’s likely the reason for the leaf drop.
Lastly, if the top 2-4 inches of soil are bone dry, then consider mulching the top of the soil to improve water retention and protect the soil from the hot sun.
While it might take a bit of practice, you can learn to quickly spot if your citrus tree is going through a stressful event and provide a quick remedy for it.
When it came to our orange tree losing its leaves in the fall, we found that it was due to a lack of water. We noticed the top few inches of soil were a bit dry, so when we increased the amount of water we provided it, the leaves perked back up and they stopped dropping.
If your citrus tree has leaf loss, it’s likely due to one of the stressors above. Like any plant in your garden, citrus trees will occasionally require a bit of troubleshooting to identify what issue is occurring and what potential fixes there are. Start by testing for one issue at a time and move forward with the process of elimination for best results.