I recently bought a bing cherry tree and it started to get some curling leaves. While there’s some information out there, most of it wasn’t helpful. So, I did some more research. Here’s what I found.
Cherry trees get curled leaves from over or under-watering, a lack of nutrients, and aphids. To help fix curled leaves, check that the top 2-4 inches of soil are moist, provide fertilizer 1-2 times per year or compost every 1-2 months, and check under the leaves for signs of aphids.
So, while several issues cause curled leaves on cherry trees, how can you tell which issue is affecting your cherry tree, and what can we do to fix it? Let’s take a closer look.
When cherry trees are under-watered, their leaves begin to curl to conserve moisture. If left for too long, the leaves will dry, brown, and drop. To prevent this, only water when the top 2-4 inches of soil is dry.
Like most plants, cherry trees need sufficient moisture in their soil to properly grow, develop fruit, and cool themselves in times of heat. When they don’t have enough water, they’ll shed less vital parts first, which usually includes the fruit, blossoms, and leaves.
So, what’s the best method to water cherry trees?
The best way to water cherry trees is to only water when the first 2-4 inches of soil gets dry. The goal should be soil moisture similar to that of a wrung-out sponge. Apply 2 inches of compost and 4-12 inches of mulch for maximum benefits.
I cannot stress just how useful compost and mulch are for cherry trees (and other plants)!
Compost adds valuable nutrients and retains great amounts of water. This higher water capacity is due to the soil’s increased richness. For example, each 1% increase in a soil’s organic matter can help hold 20,000 gallons more water per acre (source).
Mulch protects the soil and its beneficial microbes by regulating soil temperature, preventing soil erosion, and further reducing evaporation. Since fruit trees evolved in the partial shade of forests, they’re used to having a good layer of fallen branches and leaves on top of their soil. Mulching is one of the best practices you can do for your fruit trees.
For best results, apply 2 inches of compost and 4-12 inches of mulch. Reapply compost every 1-2 months and mulch every 3-6 months. Keep these materials at least 3 inches away from your cherry tree’s trunk to prevent mold from growing.
2. Extreme Heat
To help prevent curling leaves, avoid exposing your cherry trees to temperatures over 90ºF. Since cherry trees are natively from temperate climates, they can’t tolerate as much heat as tropical plants such as citrus trees.
Additionally, cherry trees need proper watering to help keep themselves cool.
Cherry trees cool themselves by sending moisture from their roots to their leaves and through a process called transpiration.
Much like humans, plants breathe and release moisture when hot. For plants, this is called transpiration. However, when the climate is too hot and dry, transpiration and root moisture can’t effectively keep up to cool the plant and its leaves. As a result, the cherry tree’s leaves curl and brown at the tips. Over time, the entire leaf will brown, followed by the whole cherry tree dying.
Hot Weather Tips
Here are some tips that will help your cherry tree survive warmer weather and the occasional heat spell:
- Compost – apply 2 inches of compost to not only provide nutrients for your cherry tree but to hold more water in the soil and help prevent drought stress.
- Mulch – similar to compost, mulch goes a long way in water retention, but also offers other benefits such as shading and insulating the soil—regulating its temperature. Provide a minimum of 4 inches of mulch for best results.
- Shade – partial shade further protects the tree’s leaves, roots, and soil from the heat. Some ideas to create shade for your cherry trees are large umbrellas, shade sails, trellises, or other plants.
In extremely hot and dry weather, cherry trees benefit greatly from partial shade. This is especially true for protection against the west, afternoon sun as it’s the hottest.
A great way to provide partial shade and add other benefits to your garden and orchard is with support species.
Support species are typically nitrogen-fixing pioneer plants (the first plants to grow in disturbed areas such as wildfires and construction zones) and provide partial shade to young productive plants until they can mature and grow a large canopy and root system.
Since productive trees such as cherry trees evolved with nearby support species, it’s beneficial to grow them together, especially while the cherry trees are young.
Some examples of support species to grow with cherry trees are black locust and alders.
3. Improper Nutrients
|Entire leaf is pale or yellow
|Dark green veins, rest of the leaf is yellowing
|Broadly pale leaves, foliage color looks mottled or smeared
Cherry trees that are over or under-fertilized become stressed, leading to curling and browning leaves. A lack of nutrients causes deficiencies, while nutrient potency from excess fertilizer causes the cherry tree’s roots to burn.
For best results, use a quality low nitrogen fertilizer such as a 5-10-10 as directed, or 2 inches of compost every 1-2 months.
Chemical Fertilizers vs Compost
While chemical fertilizers have nutrients in quantity, they typically lack nutrients in quality. This can cause stress for the cherry trees as they’re unable to absorb sufficient nutrients. Additionally, much of the nutrients from chemical fertilizers are often leached through the soil when watering.
Chemical fertilizers can also have other, unintended consequences, such as killing beneficial soil life and drying out the soil.
Fortunately, compost and manure have been found to contain more than sufficient nutrients for plants (including cherry trees), potentially even replacing fertilizer.
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.”University of Massachusetts Amherst
Compost also feeds beneficial soil life such as earthworms and mycorrhizal fungi, leading to benefits such as improved soil aeration, nutrient availability, and disease resistance.
Mycorrhizal fungi promote many aspects of plant life, in particular improved nutrition, better growth, stress tolerance, and disease resistance.Department of Biology, University of Fribourg, Switzerland
However, if you’re not big on compost, you can find out more about the fertilizers that I do recommend for cherry trees on my recommended fertilizer page.
Keep in mind that nutrients aren’t everything. Cherry trees also need a specific soil pH to properly absorb nutrients and thrive.
Cherry trees prefer a soil pH between 6.0-7.0.
This is important because an acidic soil pH dissolves the solid nutrients in the soil, and makes them available to be absorbed by the plant’s finer roots.
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, SUNY College of Environmental Science and Forestry
Two good ways to check the soil’s pH are with pH strips or a pH meter. I prefer using a meter since they’re affordable and easy to use. To see which pH meter I use and recommend, view my recommended tools page.
Aphids are small bugs that suck the sap from underneath the cherry tree’s leaves, causing the leaves to curl and fall off. You can get rid of aphids by spraying them with water, spraying them with neem oil, or by releasing ladybugs (a natural predator of aphids). Typically, a jet of water is enough to get rid of them.
While aphids are a pain to deal with, they’re generally not too difficult to remove. I once had a lot of aphids on my Kaffir lime tree and found that a jet of water was all that was needed to knock them off of the leaves and prevent them from coming back.
If you do use water to wash the aphids off, make sure the jet isn’t too strong as it can damage the leaves. For me, I simply fit my thumb over the nozzle and found it was enough pressure to dislodge the aphids without damaging the leaves.
If that doesn’t work, spray them with neem oil to render them immobile (and die off), or use ladybugs in your garden. You can find both neem oil and ladybugs in most gardening stores or nurseries.
Additionally, some companion plants such as nasturtium keep aphids away from your plants. I recently wrote a post on the best companion plants for cherry trees, so check it out if you’d like.
More Tips to Care for Cherry Trees
- Cherry tree’s soil should be well-draining but stay moist for at least a couple of days. If your cherry tree’s soil has poor drainage (common with clay soils), then consider elevating it to a mound or raised bed to let gravity assist with the drainage. Additionally, amend the soil with compost and sand to break up the larger clumps.
- Cherry trees grow in USDA hardiness zones 5-7. Generally, sour cherry tree varieties are hardier than sweet varieties. You can keep cherry trees cool by mulching their soil, providing sufficient water, and creating shade during the afternoon sun. On the other hand, keep cherry trees warm by planting in a south-facing direction to maximum sunlight (if you live in the southern hemisphere, this is north). You can also plant it along a south-facing wall to have some heat and sunlight reflected onto the plant.
- Plant cherry trees at least 25 feet away from other trees and structures. Any closer and their roots will compete for water and nutrients. Additionally, keeping them at least 25 feet away from structures such as house foundations, walls, fences, pipes, and fire hydrants will help prevent costly damage. You can check out my recent post on the invasiveness of cherry tree roots for more information.