A friend of mine has a few cherry trees and one of them is developing yellow leaves. Concerned, they asked me if I knew anything about it and how to treat it. I had an idea, but I did some more research to give them the best answer I could. Here’s what I found.
Cherry tree leaves normally yellow and drop in the fall and winter as the tree enters dormancy. However, if its leaves are yellowing in the spring or summer, the tree is most likely stressed from over-watering, extreme heat, improper nutrients, a lack of sunlight, or disease.
So, cherry trees get yellow leaves for several reasons, but how can we tell which issue is causing it, and from there—how do we fix it? Let’s take a closer look.
1. Seasonal
Cherry trees are deciduous plants, so their leaves naturally turn yellow, red, brown, and drop in the fall and winter. This is a survival strategy many plants picked up to successfully live in cooler, more temperate climates. By shedding their leaves, the plants enter a dormant state—similar to a bear hibernating.
Typically, deciduous plants require chill hours to stay in dormancy (under 45ºF). Sweet cherry trees require around 700-800 chill hours, while sour cherry trees prefer 1200 chill hours or more.
Cherries tend to have very high chilling requirements, between 700 to 800 hours or about 28-32 days continuously exposed to 45 degrees or less for sweet cherries and over 1200 hours or 48 days for sour cherries.
Gay Wilhelm, Placer County Master Gardener, University of California Cooperative Extension
Depending on the variety, the tree can become damaged or die if temperatures drop below -30ºF.
On the other hand, evergreen plants keep their leaves year-round. These plants either developed other ways to survive the cold, or live in tropical climates (with little to no frost).
So, if your cherry tree has yellow, red, or brown leaves in the fall or winter, know that this is normal. Leaves with discolored spots are different and can indicate disease (more on this later).
If this is the case for you—you shouldn’t need to fix anything. Just ensure it doesn’t get too cold for your cherry trees (-30ºF or below for most cherry trees) and wait for spring!
However, what happens if your cherry tree has yellow leaves in the spring or summer?
2. Over-Watering
The most common reason why cherry trees get yellow leaves is stress from over-watering. This is especially common in soils with poor drainage.
Over time, waterlogged soil can develop mold and lead to root rot (also called Phytophthora root and crown root). Root rot slowly decays the cherry tree’s roots, turning the leaves yellow, and over time, can kill the plant (more on root rot later).
So, what’s the optimal way to water cherry trees?
The best way to water cherry trees is to only water when the top 2-4 inches of soil is dry. You can check this by pushing a finger into the soil. Water until the soil is saturated down to 2 feet deep. Additionally, provide 2 inches of compost and 4 inches of mulch such as leaves, bark, straw, or pine needles.
By watering the soil down to 2 feet, you’re providing 90% of the cherry tree’s roots with water.
Also, by only watering when the soil is dry, you’re preventing both under-watering and over-watering. This helps the plant establish water independence.
Cherry trees that are watered with frequent and light watering typically only grow extremely shallow roots. After all, why would they grow deeper roots if the water and nutrients are only on the surface?
This keeps the plant at a disadvantage as their shallow roots mean they’re poorly prepared for windy weather and droughts.
So, if you want your cherry tree to be more self-sufficient and have a better chance of surviving the occasional drought, water it only when the soil is dry and down to 2 feet deep.
However, soils that have poor drainage (common with clay soils) can complicate this process.
Generally, planted cherry trees are hard to amend as there are large volumes of soil (needing large amounts of amendments). Because of this, the best way to amend garden soil for better drainage is to apply 2 inches of compost on top of the soil every 1-2 months. Over time, the smaller particles will work their way into the deeper soil.
You can provide a few inches of mulch to help this process, but avoid excessive mulching at this time it can further lock in the moisture in the poorly draining soil.
On the other hand, potted cherry trees with poor drainage can be amended fairly quickly by repotting them with fresh potting soil. Since the roots are limited to the pot, they generally don’t get as much transplant shock as digging up planted cherry trees with spread-out and established roots.
But, what if we’re watering our cherry tree correctly? What do we check next?
3. Improper Nutrients
Excess Nutrients
Excess nutrients are typically caused by over-fertilizing cherry trees. This can lead to the cherry tree’s roots chemically burning, causing the tree stress and developing yellow leaves. Normally, fast-release fertilizers are the cause of over-fertilization as compost isn’t potent enough.
Lack of Nutrients
| Nutrient Deficiency | Leaf Symptom |
|---|---|
| Nitrogen | Entire leaf is pale or yellow |
| Iron | Dark green veins, rest of the leaf is yellowing |
| Zinc | Yellow blotches |
| Manganese | Broadly pale leaves, foliage color looks mottled or smeared |
A lack of nutrients also causes stress for the tree, which then develops yellow leaves. Insufficient nutrients are commonly caused by poor soils, leaching, and other stressors.
Nutrient leaching is when the soil has too much drainage or is over-watered and the nutrients seep too far down into the soil, out of reach of the tree’s roots.
The Best Way to Fertilize Cherry Trees
You can choose to fertilize your cherry tree’s soil with fertilizer or compost.
Generally, while chemical fertilizers have nutrients in quantity, compost has quality nutrients. What this means is that over the short term, chemical fertilizers can out-perform compost, but over the long term, they often cause soil damage. This damage leads to dry soil and decreased pest and disease resistance.
On the other hand, compost provides more than sufficient nutrients, increases water retention, and promotes healthy soils. For example, every 1% increase in the soil’s richness (organic matter) leads to 20,000 more gallons of water absorbed per acre (source).
Either way you go, if you’d like to see which fertilizers I recommend, check out my recommend fertilizer page.
Soil pH
Aside from nutrients, keep in mind that cherry trees need a balanced soil pH between 6.0 to 7.0 (source).
The reason why cherry trees prefer soil with a slightly acidic pH is that it’s the ideal pH to dissolve nutrients in the soil.
Fourteen of the seventeen essential plant nutrients are obtained from the soil. Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils.
Donald Bickelhaupt, Instructional Support Specialist, Department of Forest and Natural Resources Management
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 cherry 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 cherry tree’s soil is too acidic (below 6.0), add alkaline materials such as wood ash, charcoal, or lime.
Additionally, cold and/or wet soils are not good at promoting nutrient uptake as the cherry tree will either be slightly dormant during the cold or too stressed in wet soils.
If you’re growing your cherry tree in a container, aim to have at least a 5-gallon pot as the tree’s roots need a bit of room to spread.
4. Lack of Sunlight
Cherry trees generally require at least 6 hours of sunlight to photosynthesize properly. Without it, their leaves turn yellow and they’re unable to develop sugars for the plant. Over time, this low energy leads to the plant’s declining health, which can potentially die.
Tips to Increase Sunlight
- Plant the cherry tree in a south-facing direction for maximum sunlight (north-facing if you live in the southern hemisphere)
- Plant the cherry tree along a south-facing wall to reflect more sunlight and heat onto the tree (some heat even persists into the night)
- Prune some overstory trees that are blocking the cherry tree’s canopy from the sun. You can also prune the cherry tree itself to allow more light to reach the mid and lower branches. This new space also increases aeration from the sun and wind—discouraging disease from spreading.
5. Disease
Cherry Leaf Spot
Cherry leaf spot is a fungus (Blumeriella jaapii) that infects leaves, flowers, fruit, and branches. Leaves are one of the most susceptible to it, which turn yellow and drop from the infection. However, the fruit is typically the first to be infected, with small purple spots developing on them. Over time, these fruits rot and turn brown.
If left unattended, the disease could spread to more leaves, continuing to yellow and drop them until the tree is bare. The stress from the infection and lack of photosynthesis from the loss of leaves can greatly disrupt the amount of energy the tree puts away. Without enough energy, the cherry tree’s immune system wouldn’t hold and the tree won’t survive for long.
Symptoms
- Purple, red, or brown spots 1/4 inch across. Apparent on leaves and fruit.
- Infected leaves eventually turn yellow and drop
- The most common season for infection is May to June, with temperatures between 58ºF and 73ºF (source).
How to Treat It
- Organic fungicide if possible (more on this later)
Phytophthora Root and Crown Rot
Phytophthora Root and Crown Rot (Phytophthora parasitica) is a fungal disease caused by damage to the tree’s crown or roots. This damage can be mechanical (such as a lawnmower or weed trimmers), frost, rodents, or waterlogging.
And cherry trees aren’t the only plants that can get this disease.
Almost all fruit and nut trees and most ornamental trees and shrubs can develop root or crown rot if the soil around the plant remains moist for prolonged periods.
Agriculture and Natural Resources, University of California
Symptoms
- Yellow, red, or purple leaves
- Poorly draining soil
- Darkened bark, gumming is possible
How to Treat It
Unlike the other diseases on this list, fungicides aren’t an option for treatment. The solution? Drying out the soil.
The Agriculture and Natural Resources program at the University of California has this to say about treating Phytophthora Root and Crown Rot, “The most important way to prevent Phytophthora root and crown rot is proper irrigation.”
My potted Kaffir lime tree had root rot a couple of years ago. I could tell because its leaves were yellowing and dropping. After pushing a finger into the soil and feeling it was sopping wet, I gently scooped some of the soil aside. The soil smelled like a swamp and was definitely starting to rot. Fortunately, after repotting it with fresh potting soil and letting the roots dry out for a few days, the tree made a full recovery!
So if you have a potted cherry tree, simply repotting it should treat this issue.
However, for planted cherry tree’s here’s what you can do to help fix it:
- Avoid standing water or soaked soil around cherry trees
- Provide sufficient soil drainage
- Divert sprinklers from hitting the tree’s trunk
- Transplant the cherry tree is necessary and elevate it above the ground level to promote better drainage
Verticillium Wilt
Verticillium wilt is caused by specific fungi in the soil (Verticillium dahliae and Verticillium albo-atrum) and slowly attacks the tree from the ground up. Because of this, symptoms include yellow and dropping leaves starting from the base of the tree. Typically, only the topmost part of the canopy will have leaves remaining.
Symptoms
- Yellowing and dropping leaves starting from the bottom of the canopy
- Branches wilting and dying
How to Treat It
Unfortunately, cherry trees that are infected with Verticillium wilt cannot be cured.
Trees and shrubs infected with Verticillium cannot be cured and will likely eventually die. However, you can extend the life of your plants by making sure that you water and fertilize properly.
Brian Hudelson, Plant Pathology, University of Wisconsin-Madison
However, proper garden care (especially watering and fertilizer) is the best way you can prolong the cherry tree’s life.
You can also have your soil tested for some diseases such as Verticillium wilt by your local cooperative extension.
Armillaria Root Rot
Armillaria root rot is caused by several species of the fungus Armillaria. Many trees and shrubs can contract this disease (including both evergreen and deciduous plants). The fungus colonizes the roots and the base of the trunk.
Symptoms
- Poor growth
- Yellow or brown leaves
- Dead branches
- Decayed roots and trunk
- Honey-colored mushrooms may grow near the tree in the fall
How to Treat It
Armillaria root rot cannot be cured since it’s caused by a variety of fungi within the soil. However, it can be managed.
Michelle Grabowski, Extension educator, and Cynthia Ash Kanner from the University of Minnesota’s Cooperative Extension recommend providing proper gardening practices to best manage and deter this disease from spreading (source).
- Provide 4 inches of mulch around the base of the cherry tree, under the canopy. Keep the mulch at least 3 inches away from the trunk.
- Provide sufficient water
- Avoid mechanically injuring the tree (lawnmowers, weed trimmers, etc)
A Note on Pesticides, Herbicides, and Fungicides
Really, the only cherry tree disease on the above list that could benefit from a fungicide is cherry leaf spot. Still, it doesn’t mean that fungicides are the best option.
My parents recently had an issue with caterpillars eating their basil plants in Ventura, CA, and they were about FED UP. Every time they’d plant basil plants, the caterpillars ate it.
Fortunately, instead of giving into chemical sprays, they found an organic spray at their local nursery that’s made from fermented rum. The day after spraying, they’d find dead caterpillars on the soil.
If you’d like to find out more about this organic spray, you can find it here on Amazon.
So, what’s my point here?
Even though chemical sprays and fertilizers are an easy way out, like all easy and convenient things, there are usually long-term costs. Namely to the plants, soil, and surrounding beneficial life. Before using chemical sprays, weigh the pros and cons and consider trying organic or permaculture-based treatments first!
To give you a head start, Stefan Sobkowiak – The Permaculture Orchard has a great video on a safe, homemade, and more importantly—effective fungicide (hint: the secret ingredient is whey).
Also, check out how Mark Shepard uses a method called STUN (Sheer-Total-Utter-Neglect) to help his berries, fruit, and nut trees THRIVE.
