A reader recently reached out and asked why their cherry tree’s leaves are turning red. While I had an idea of what was causing it, I did more research to give them the best answer I could. Here’s what I found.
Cherry tree leaves naturally turn red and drop in the fall. However, if your cherry tree is getting red leaves in the spring or summer, it’s likely Leaf Spot disease, aphids, a lack of nutrients (especially phosphorus), or Peach Tree Leaf Curl disease. Start by inspecting the leaves for spots or aphids underneath.
Here are the 5 most common reasons cherry tree leaves turn red (in order):
- Leaf Spot Disease
- Lack of Nutrients
- Peach Tree Leaf Curl Disease
Now, let’s take a look at how to identify what’s causing our cherry tree to get red leaves, and how to fix it.
Cherry trees are deciduous trees, so it’s normal for their leaves to drop in the fall and winter. Often, this means leaves turning yellow, orange, and red before falling from the tree. Other deciduous trees include apples, pears, and peaches.
These trees shed their leaves in the fall to go dormant and withstand the winter. In the spring, they’ll regrow new leaves, if they’re still healthy.
On the other hand, evergreen trees keep their leaves year-round. They include citrus, avocado, and mango trees. These trees don’t shed their leaves as they’re adapted to warmer climates, experiencing little to no frost.
Keep in mind, the new growth on cherry trees is also often red, turning green as the leaves mature.
But, what if your cherry tree is getting red leaves in the spring or summer? What could be causing it then?
2. Leaf Spot Disease
Leaf Spot (Blumeriella jaapii) is a fungal disease that causes red spots on a cherry tree’s leaves. It’s spread by the infected leaves from the previous winter. In the spring and early summer, the spores are splashed upwards and onto the leaves, where they continue spreading.
This disease commonly starts in the early spring, when temperatures start warming and the spring rains arrive. The infected leaves continue spreading in May and June, and by July, the cherry tree can lose all of its leaves.
The easy way to identify Leaf Spot disease on cherry trees is if you see red or purple dots on your cherry tree’s leaves. The spots are about 1/4 inch and turn eventually brown. These infected leaves drop from the tree within around one month.
How to Treat
The best way to prevent leaf spot on cherry trees is to rake and compost all of the fallen leaves in the autumn. Since the spores survive the winter on the fallen leaves, removing all of the leaves significantly reduces the chances the spores infect the tree again the following spring.
Sprays are not recommended unless your cherry tree has had leaf spot before and lost all of its leaves for several years in a row. To learn more about fungicides for leaf spot, see this guide by the University of Minnesota Cooperative Extension or contact your local cooperative extension office.
Aphids, sometimes called cherry blackflies, are small bugs that suck the sap from a cherry tree’s leaves, causing them to curl and often turn red. These bugs also leave behind a sticky residue called honeydew, which attracts ants.
If left unchecked, aphids continue damaging the cherry tree’s health and potentially stunting its growth or killing the tree.
How to Treat
The best ways to get rid of aphids on cherry trees are:
- Spraying the leaves with a jet of water
- Spraying the leaves with neem oil
- Attracting ladybugs (a natural predator of aphids)
Most often, a jet of water is enough to knock aphids off and kill 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 sufficient 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. Just keep in mind that too strong of a blast can damage the leaves.
To attract ladybugs to your garden, you can plant cherry tree companion plants such as dill, fennel, and yarrow.
4. Lack of Nutrients
If your cherry tree’s leaves have a yellow or red tint in the spring and summer, and they’re not spotted (leaf spot) or curling (aphids or peach tree leaf curl), then it’s likely a lack of nutrients causing the issue.
Here’s a table of the most common nutrient deficiencies for cherry trees:
|Entire leaf is pale or yellow
|Dark green veins, rest of the leaf is yellowing
|Broadly pale leaves, foliage color looks mottled or smeared
However, it’s said that insufficient phosphorus contributes to cherry tree leaves turning red.
“[Phosphorus] deficiency can lead to reduced growth and stunting and red dark coloration of leaves because of enhanced anthocyanin pigments.”Bernardita Sallato, Tree Fruit Extension Specialist, Washington State University
How to Treat
Here’s how to treat cherry trees with a nutrient deficiency or imbalance (including phosphorus).
- Apply Slow-Release Fertilizer
- Provide Compost & Mulch
- (Optional) Supplement with Bone Meal
- (Optional) Check the pH is Balanced
I recommend starting by applying fertilizer once a year in the early spring (after the last frost, but before the new growth). This provides your cherry tree with sufficient nutrients to leaf, flower, and fruit properly.
Plants require three primary nutrients: nitrogen, phosphorus, and potassium (abbreviated as NPK). For example, the fertilizer in the image above has an NPK of 6-2-4, or 6% nitrogen, 2% phosphorus, and 4% potassium.
Nitrogen is used for leaf and root growth, phosphorus is mainly for flowering and fruiting, and potassium is used for the plant’s overall health. Cherry trees prefer a balance of all three of these nutrients.
However, trace or secondary nutrients such as iron, copper, and magnesium are also important and included in most fertilizers and compost.
Deficiencies of any nutrient lead to issues such as red or yellow and dropping leaves, or poor flowering and fruiting.
To see the fertilizers I use and recommend, see my recommended fertilizer page.
However, there are two other essential practices when it comes to fertilizing fruit trees.
2. Compost & Mulch
Apply 2 inches of compost and 4 inches of mulch.
Compost provides essential nutrients, improves the soil’s health, and increases water retention. For example, every 1% increase in the organic matter of the soil holds an additional 20,000 gallons of water per acre.
Mulch dramatically reduces evaporation, regulates soil temperature, and prevents soil erosion. It also provides the cherry tree with extra nutrients and blocks weeds from growing. Use mulches such as leaves, bark, straw, and pine needles.
These two practices also help prevent cherry trees from being under-watered and drought-stressed.
3. (Optional) Supplement with Bone Meal
If you believe your fertilizer and compost aren’t providing enough phosphorus to help treat your cherry tree’s red leaves, consider supplementing it with bone meal.
Bone meal has an NPK of 3-15-0, so it’s high in phosphorus. Applying this amendment should fix any phosphorus deficiency in the soil.
To apply, use 1 cup of bone meal for every 2 inches of trunk diameter. Apply under the cherry tree’s drip line (canopy) and lightly mix into the soil. Follow it with moderate watering to allow the bone meal to seep to the roots.
You can see the bone meal I use and recommend on Amazon.
4. (Optional) Imbalanced pH
Cherry trees prefer a soil pH between 6.0 to 7.0.
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. Without this, nutrients can be “locked” in the soil and not able to be absorbed by the plant’s roots. This commonly leads to issues such as red, yellow, and dropping leaves.
“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. 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 (ground limestone).
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.
5. Peach Tree Leaf Curl Disease
Peach Tree Leaf Curl, also known as leaf curl, is a disease most commonly infects peach, nectarine, and almond trees, but cherry trees can be infected in rare cases. It’s caused by the fungus Taphrina deformans.
You can tell if your cherry tree has leaf curl disease if its leaves are turning red and are severely curled or distorted. However, flowers, fruit, and shoots are also affected. This disease is most common in the spring, when the weather is wet and warm, and usually infects young leaves within 2 weeks of budding.
Over time, the infected leaves turn yellow and brown, and drop from the tree.
How to Treat
The best way to prevent leaf curl disease is to grow resistant varieties of cherry trees. Because leaf curl is rare with cherry trees, I wasn’t able to find much information on resistant varieties (however, your local cooperative extension would know more).
Otherwise, according to the University of California Integrated Pest Management Program, spray the tree every year when the tree is dormant (after the leaves have fallen).
To learn more about this disease and the sprays recommended, see this guide by the University of California or contact your local cooperative extension office.
Also, Stefan Sobkowiak – The Permaculture Orchard has a great video on a safe, homemade, and more importantly—effective fungicide (hint: the secret ingredient is whey).