We have lots of fruit trees in our backyard including lemon, lime, tangerine, fig, and avocado, and while most of them are doing well, some are losing their leaves. So, to find out more, I did some research. Here’s what I found about fruit trees shedding their leaves.
Fruit trees commonly drop their leaves due to seasonality or a stressful change in watering, nutrients, or environment. Additionally, pests and diseases such as aphids, root rot, and blight cause fruit trees to lose their leaves. After resolving the issue, the tree should regrow its leaves by spring at the latest.
So, while fruit trees lose their leaves for multiple reasons, how can we tell which one is causing it, and what can we do to fix it? Let’s take a closer look.
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|Deciduous Fruit Trees||Evergreen Fruit Trees|
Temperate fruit trees such as apple, pear, and cherry are deciduous, so they normally lose their leaves in the fall. Their leaves typically turn yellow and brown before they drop. Usually, temperate fruit trees are those that do best in USDA hardiness 8 and below (as these zones get the most frost).
The reason why deciduous trees drop their leaves in the fall is for survival. By shedding their leaves, they’re preserving resources so they can go dormant, waking when spring arrives (similar to a bear hibernating).
As a result, deciduous fruit trees require 200 to 1500 chill hours (every hour under 45ºF) per year (source). These cool temperatures allow them to maintain their hibernation, or dormancy.
If the winter temperatures get above 45ºF, the fruit trees start to come out of dormancy and can face issues. The most notable issue is if they wake and start blossoming (thinking spring has arrived), only to have a later frost kill the vulnerable flowers. This can prevent them from fruiting successfully until the following season.
On the other hand, many evergreen fruit trees (such as citrus trees) are native to the tropics and experience little to no frost. So, they had no need to develop survival strategies to survive the winters. As a result, they keep their leaves year-round.
The evergreen trees that do experience regular frost (like pine trees) have adapted to have other ways of surviving the winters. For example, in his book, The Hidden Life of Trees, professional forester Peter Wohlleben found that pine tree needles have a type of anti-freeze, allowing the tree to keep their leaves throughout the winter.
So, if your deciduous fruit tree’s leaves are turning yellow, red, and dropping in the autumn, know that this is normal and they’ll regrow their leaves in the springtime.
However, what happens if your deciduous fruit tree is dropping its leaves earlier in the year (spring and summer), or your evergreen fruit tree is losing its leaves? What could be causing it then?
2. Under or Over-Watering
Under and over-watering causes fruit trees to lose their leaves quickly. Typically, under-watering symptoms include leaves curling, drying, and browning before they fall off. On the other hand, over-watering symptoms are dropping green leaves and swampy-smelling soil. Over time, this leads to root rot, a water mold, which decays the roots and can kill the fruit tree.
So, what’s the best way to water and prevent both under and over-watering?
Ideally, only water fruit trees when the first 2-4 inches of soil are dry. You can check this by pushing a finger into the soil. This is the best way to prevent both under and over-watering while promoting the tree’s water independence.
However, there are times when the soil has poor drainage. In this case, the soil likely needs to be amended before continuing a regular watering practice.
If you have a potted fruit tree, the best way to amend its soil is by repotting the tree with fresh potting soil. It’s also a best practice to repot the tree into a larger pot every 3-5 years to prevent root binding.
But, if you have a fruit tree planted in the ground, it can be difficult to amend its soil. For this, add organic amendments such as sand or compost to improve the soil’s drainage. Apply 2 inches of compost every 1-2 months on top of the soil.
For fruit trees that have not yet been planted in the ground, and you have heavy clay soil, it’s often best to plant them in mounds of soil. For more information about planting in clay soil and why mounds are the best way to plant, check out my other post: Can Fruit Trees Grow in Clay Soil (& How To Plant Them)?.
Once your fruit tree’s soil is well-draining, apply 2 inches of compost and 4 inches of mulch to promote better water management.
Compost is great at not only providing sufficient nutrients (more on this later) but increasing the soil’s richness—every 1% increase in the soil’s richness holds an additional 20,000 gallons of water per acre (source).
Mulch brings benefits such as regulation of soil (and root) temperature, reduced evaporation, and added nutrients once the mulch breaks down.
Remember to keep the compost and mulch at least 3 inches from the fruit tree’s trunk to prevent moisture build-up (which can lead to mold).
3. Improper Nutrients
Excess nutrients are typically caused by over-fertilizing fruit trees. This can lead to the potential burning of the fruit tree’s roots, causing the tree stress and developing yellow and dropping leaves. Normally, fast-release fertilizers are the cause of over-fertilization as compost isn’t potent enough.
If you do think your fruit tree has been over-fertilized, the best way forward is to stop applying fertilizer and deeply water the tree (down to 2 feet or more). As long as your fruit tree doesn’t have poor drainage, the water will leach the excess nutrients further into the soil (out of reach for the fruit tree’s roots), where the nutrients can then be broken down.
Lack of Nutrients
|Nutrient Deficiency||Leaf Symptom|
|Nitrogen||Entire leaf is pale or yellow|
|Iron||Dark green veins, rest of the leaf is yellowing|
|Manganese||Broadly pale leaves, foliage color looks mottled or smeared|
On the other hand, a lack of nutrients can also cause fruit trees to drop their leaves. This is typically from a nitrogen deficiency. Although, other deficiencies can also cause it.
If your fruit tree’s leaves fit any of the above descriptions in the table, it can be a good indicator one of those nutrients is lacking in the soil. While nitrogen is the primary nutrient plants need, iron, zinc, and manganese are important trace, or secondary nutrients.
However, this table is not black and white as sometimes there’s a combination or range of issues and symptoms. If you’d like a more definitive nutrient profile of your soil, consider reaching out to your local cooperative extension as they commonly have soil tests available for your area.
How To Fertilize Fruit Trees
For best results, provide the fruit tree with a quality 10-10-10 NPK fertilizer (nitrogen [N], phosphorus [P], and potassium[K], the primary nutrients for plants) or compost. These amendments provide sufficient amounts of primary as well as trace nutrients.
While chemical fertilizers have nutrients in quantity, many growers are finding they are lacking in quality and lead to issues such as poor water retention, declining soil health, and increased pests and disease.
As a result, many are learning that compost and manure not only have nutrients in both quantity and quality, but they can even replace fertilizers.
“Approximately 70-80% of nitrogen (N), 60-85% of phosphorus (P), and 80-90% of potassium (K) found in feeds is excreted in the manure. These nutrients can replace fertilizer needed for pasture or crop growth, eliminating the need to purchase fertilizers. Plants do not distinguish between sources of nutrients. However, compared to commercial fertilizer, manure contains organic carbon which is the key to maintaining soil health, including the characteristics of cation exchange capacity, soil tilth, and water holding capacity.”University of Massachusetts Amherst
While it may be hard to believe, chemical fertilizers were only invented in 1903 and plants have been thriving without them for many hundreds of thousands of years.
If you’d like to learn more about how compost can sufficiently replace and even outperform fertilizers in the long run, feel free to see my other post: Can Compost Replace Fertilizer? Here’s What the Experts Say.
Imbalanced Soil pH
However, nutrients aren’t the entire picture. Without a proper pH, the soil can be too acidic or too alkaline for fruit trees, resulting in them not being able to absorb nutrients from the soil.
The majority of fruit trees prefer a soil pH of 6.0-7.0.
The reason why fruit trees (and most plants) prefer a slightly acidic pH is because it dissolves the solid nutrients to be absorbed by the plant’s finer roots (source). Without a sufficient pH, even if the soil has nutrients, the fruit trees can’t absorb them and develops issues such as leaves dropping.
Two good ways to check your soil’s pH are either by using a pH strip or a pH meter. I prefer using a pH meter since they’re affordable and easy to use. To see which pH meter I use and recommend, check out my recommended tools page.
If you find that your fruit tree’s soil is too alkaline (above 7.0) you can add acidic amendments such as coffee grounds, sand, and peat moss. On the other hand, if your fruit tree’s soil is too acidic, add alkaline materials such as wood ash, charcoal, or lime.
Additionally, cold and/or wet soils are not sufficient for proper nutrient uptake as the fruit tree will either be slightly dormant during the cold or too stressed in wet soils.
If you’d like to see which fruit tree fertilizers I recommend, check out my recommended fertilizer page.
4. Extreme Weather
While each variety of fruit tree prefers its own specific temperature, they still get stressed when there’s an early frost, extreme heat, or a swing in weather. This stress causes the tree’s leaves, blossoms, and fruit to brown and drop. To prevent this, monitor swings in weather and shelter the tree if possible.
When fruit trees get too hot, their leaves start to dry, brown, and drop. The hot weather also dries the soil, making the issue even worse as the tree’s roots can’t send enough moisture to its leaves and help cool them.
On the other hand, deciduous fruit trees can normally tolerate cold temperatures fairly well. Again, this is due to them shedding their leaves in the fall and entering dormancy to survive the cold winters.
Because of this, most deciduous fruit trees do best in USDA hardiness zones 4-8, but some varieties can survive in zones 3.
|Fruit Tree||Growing/Hardiness Zone*|
However, too much cold will kill fruit trees (especially many evergreen or tropical varieties). Typically, deciduous fruit trees will be dormant for the winter and have a good chance of surviving the low temperatures, but an unexpected frost after the tree wakes can damage or stunt it.
If your climate gets too hot or cold for your variety of fruit trees, there are some steps you can use to help protect your tree.
Hot Weather Tips
- Provide 2 inches of compost and 4 inches of mulch. Compost provides valuable nutrients and increases the water retention of the soil (source), while mulch regulates soil temperature and reduces evaporation. Reapply compost every 1-2 months and mulch every 3-6 months.
- Shade fruit trees from the afternoon sun. Since the western, afternoon sun is much hotter than the eastern, morning sun, shade the tree for a least a few hours from its west side. Some ideas to shade are large umbrellas, shade sails, or other trees.
- Move potted fruit trees indoors during heat waves. Try to move them gradually over two weeks as to not stress them out from the swing in temperature. If you can move them to a patio with shade, that’s even better.
Generally, while hot weather more commonly leads to brown and dropping leaves, extremely cold weather can also cause it.
Cold Weather Tips
- Insulate the tree’s canopy with bedsheets or the trunk with cardboard during times of too much frost. Plastic tarps also work well, especially at preventing ice build-up.
- Bury the pot or provide a mound for planted trees. Potted fruit trees can be buried outside in the ground for more insulation. You can also place the pot in a box and pack in the remaining space with mulch. Planted fruit trees can benefit from a 1-2 foot high mound of mulch such as leaves during the winter.
- Place fruit trees along a southern-facing wall for maximum sunlight and warmth. Generally, facing south allows for the most sunlight (as it receives both the sunrise and sunset). Also, as night falls, some warmth will continue radiating from the wall onto the tree.
- Avoid bringing most potted deciduous fruit trees indoors during the winter as they require chill hours. Indoor temperatures, including basements, rarely fall and stay below 45ºF necessary for chilling.
5. Transplant Shock
If a fruit tree was recently planted or repotted, and it’s starting to die, it’s likely due to transplant shock. Transplant shock occurs when the plant is exposed to a new environment and has to establish a new root system. Avoid transplanting unless necessary as it can take up to 1 year for recovery.
To help avoid transplant shock, I like to plant with the following steps in mind:
- 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 2 inches of compost and 4 inches of mulch to the top of the soil
- Water generously and add more soil as needed
6. Pests and Diseases
Aphids and Mites
Aphids are small bugs that suck the sap from underneath the fruit tree’s leaves. This loss of sugar and moisture causes the leaves to curl, yellow, and drop. They also deposit honeydew, which attracts ants. If left unchecked, aphids can damage the fruit tree’s health and potentially stunt or kill it.
These bugs come in multiple colors including white, yellow, or black, and usually hide underneath the leaves. Typically, aphids won’t cause damage to the fruit, but because they suck sap from the trees, they can compromise its health and therefore reduce fruit size.
The best ways to get rid of aphids and mites on fruit trees are by spraying the infected leaves with water or neem oil, or releasing ladybugs (a natural predator to aphids and mites). Most often, a jet of water is enough to get rid of them, but neem oil is a good second option.
For example, when my potted Kaffir lime tree had aphids, I found that a jet of water was enough to blast them off and prevent them from coming back. All I did was remove the hose nozzle and used my thumb to increase the pressure. Keep in mind that too strong of a blast will damage the leaves.
Root rot, or Phytophthora root and crown rot, are fungus-like water molds that affect most, if not all fruit trees. Causes of root rot are typically over-watering or soils with poor drainage. Symptoms include leaves wilting, discoloring, stunting, and dropping (source).
You can typically tell if your fruit tree has root rot if the soil is staying sopping wet and starts smelling.
As another example, my potted Kaffir lime tree also had root rot at one point. I only found out because its soil was staying soaking wet days after watering and it started smelling like a swamp. Luckily, all that the tree needed was to be repotted with fresh, dry potting soil (to amend the drainage and soak the excess water) and it quickly started to recover.
Verticillium wilt is a fungus that is similar to root rot, in that it usually occurs in soils with excess water. Additionally, over-fertilizing can also cause it. The most susceptible fruit crops that contract verticillium wilt are nightshade (tomatoes, peppers, and eggplants), but fruit trees can also be infected. Symptoms of this disease include leaves wilting, yellowing, and dropping, with potentially branch dieback (source).
You can prevent and treat verticillium wilt by pruning infected branches, avoiding excess water and fertilizers, and following best gardening practices.
Fire blight (Erwinia amylovora) is a highly infectious and common bacterial disease that affects members of the rose family—including apple, pear, crabapple, rose, cotoneaster, mountain ash, hawthorn, quince, spirea, and pyracantha. Fire blight causes browning and disfiguring of the leaves and fruit, sometimes killing the tree.
Unfortunately, there is no cure for fire blight. However, there are still many things you can do to prevent and manage this pear tree disease.
Research from Washington State University has shown that oregano, thyme, and cinnamon essential oils are a viable treatment for fire blight. Simply use a spray of 23% thyme oil or 60% cinnamon oil on the tree a few times per year. Additionally, you can use vinegar as it’s a natural disinfectant.
If you’d like to see more about treating fire blight, see my other post: Fire Blight Treatment: Non-Organic & Organic Solutions.
To see a more complete list of the pests and diseases that fruit trees can get, check out this resource by The University of California, Agriculture and Natural Resources Statewide Integrated Pest Management Program.