Cherries have always been my favorite fruit (sorry lemons, cherries take the cake). Which is why cherry trees are on my list to grow on my homestead. If you didn’t know, cherry trees usually take 3-5 years to mature, so, seeing yellow leaves (also called chlorosis) is a cause for concern, especially while the tree is young. So, what causes cherry tree leaves to yellow and drop?
Yellow and dropping leaves on a cherry tree can be explained by insufficient watering or nutrients, or from a bacterial or fungal disease. Many diseases cannot be cured, but their damage can be limited so the tree can get the chance to recover.
So, how do you know how much to water or fertilize your cherry tree? What do these diseases look like? And how can you prevent or reduce their damage?
We’ll get to these questions, but first, let’s take a further look at what exactly causes yellowing and dropping leaves on cherry trees.
What Causes Yellow and Dropping Leaves on Cherry Trees?
Leaves falling on your cherry tree might not be attributed to a disease or improper watering, but could be from natural leaf fall. As you might have guessed, this can often occur in the fall when temperatures drop. This is a natural process and helps to preserve resources for the tree during the colder seasons.
If this is your first year with your cherry tree, know that it’s perfectly normal for cherry trees to develop yellow leaves and shed them over the winter. While your tree might be bare, it’s likely very much alive, just in a dormant state. The most important action you can take at this time is making sure your cherry tree doesn’t freeze during the winter.
At the same time, don’t keep your tree too warm. Many varieties of cherry trees do best with cooler temperatures.
In fact, cherry trees prefer having around 2 months of chilly weather that’s lower than 45ºF. Having a certain amount of cooler nights allows them to develop a large yield of fruit. It’s suggested that a good number for a sizable harvest is about 800 hours of chilly weather. In short, 1-2 months of temperature under 45ºF can help promote a good fruiting season.
On the other hand, if temperatures get too hot, it could cause cherry tree leaves to yellow and drop off prematurely.
Cherry trees don’t do well in hot weather, and do even worse and lose more leaves when their nutrients are unbalanced. Clay soil is often a cause of nutrient imbalance as it typically has poor drainage and high alkalinity on the pH scale. By not having the right pH, cherry trees might not be able to absorb the proper nutrients from the soil. Aim for a soil pH of 6.0-6.5, which is considered acidic. Balancing pH and providing proper fertilizer can ensure the best chance of nutrient uptake and lead to a healthy cherry tree.
When fertilizing, the best mix for cherry trees is one with low nitrogen (a 5-10-10 NPK will work well) along with organic compost. It’s best to only fertilize in the spring, and not fall or winter as the tree will naturally become dormant and not require as many nutrients.
Nutrient deficiencies from either alkaline or nutrient-poor soil can include several kinds of elements. Some examples are the macronutrients: nitrogen, phosphorus, and potassium, as well as micronutrients, such as iron, copper, and zinc.
There’s also the chance that overwatering can flush many of the nutrients away, which means you might need to fertilize or reapply compost sooner.
Using a fertilizer low in nitrogen is key for cherry trees to encourage less leaf growth and more fruit growth.
Even if you fertilize your cherry tree the recommended one time per year, there could be nutrients missing or unable to be absorbed from the soil. For this reason, make sure to check the pH at least once per year.
If you find your cherry tree’s soil is too alkaline, try mixing in some sandy loam soil and supplement with fertilizer. Compost can also ensure the cherry tree is receiving the full spectrum of easily accessible nutrients. Avoid using biochar or wood ashes to fertilize as these naturally have very high alkalinity.
Both over and underwatering can cause leaves to yellow and drop. In general, it’s best to water cherry trees with a deep watering every 1-2 weeks. It can be difficult to know exactly how much to water them because of their unique climate, dryness, and soil composition, but if you see the cherry leaves perk up after watering, it’s usually a sign they were underwatered.
On the other hand, it can be difficult to tell if it’s getting too much water. The best way to know if you’re overwatering is to check the cherry tree’s soil to see how long it stays wet. If the soil holds the same or similar amount of moisture 24 hours after watering, there’s a chance the soil isn’t draining properly and will need to be amended with sand or more porous soil.
There’s also the possibility that your cherry tree is getting overwatered due to its placement. If you’ve planted it in your lawn, or at the base of a hill, it could be getting too much water. If you’re not sure if your cherry tree is getting overwatered, consider getting a moisture meter before relocating it.
Moving on from natural causes and watering, let’s take a look at some of the most common bacterial diseases cherry trees can develop and how to remedy them.
Bacterial canker is a type of bacteria that can form on cherry trees during wet and cool weather. Most often, this occurs in spring. While it can take a while for it to set in, the bacteria can turn leaves yellow and drop them from the trees. You can spot bacterial canker by the large brown spots spreading across leaves.
Prevention and recovery is possible if you prune the infected areas carefully. Try to avoid pruning in the peak seasons (spring and fall) if possible due to the increased number of bacteria. When pruning, cut above the infected area and seal with a pruning sealer or wax. Disinfect the pruning shears after each cut to reduce the chance of spreading the bacteria to other branches or trees.
Bacterial spot is caused by another bacteria species, only this time you can see small holes developing in the leaves. The affected leaves will be yellow and have small spots that are brown or black in color along with holes that have a red outline. Eventually, the leaves will drop. Especially during wet and windy weather, the bacteria can also spread to the cherries, which causes dark spots and a shriveled fruit. You can limit the spread of bacterial spot by avoiding high nitrogen fertilizers and using a copper-based fungicide.
Cherry Leaf Spot
Cherry leaf spot is a fungus that creates yellow and brown spots on the top of the leaf, and occasionally have a white fuzz underneath it. If left unattended, it will cause leaves to drop. The peak time for this disease is mid to late spring due to the heavier rains and wet conditions. If left unattended, the cherry tree might not have any leaves left by the summer. The best ways to treat cherry leaf spot is to use an organic fungicide and by pruning off the infected leaves.
Another fungal disease, verticillium starts from the tree’s roots, which is why it’s important to use a healthy rootstock that’s resistant to fungus. This fungus will turn the leaves pale and drop them (usually in the summer). Infected branches can transmit the fungus to other branches and if not managed over 1-3 years, the cherry tree can become stunted. You can help prevent verticillium by limiting weeds, avoiding high nitrogen fertilizers, and watering properly. Recovery is possible if you prune the infected branches and provide proper watering and nutrients.
Root rot is a fungus that is usually caused by overwatering and stagnant water. The fungus can cause yellowed and stunted leaves that quickly drop off the tree. You can manage root rot by checking for proper drainage and reconstituting the soil if it’s been soaked for an extended period. You can also temporarily remove some of the soil around the tree to improve aeration and allow it to dry. Just be careful not to leave the roots exposed.
If you need to repot or plant your cherry tree and would like some guidance, check out the helpful video below by Our Little Homestead.
It can be hard to tell exactly what’s causing your cherry tree’s leaves to yellow and fall off, but you can start by inspecting both the leaves and the soil. If the leaves have any spots or white fuzz underneath, then there’s a good chance it’s one of the diseases listed above.
Additionally, if you check the soil and find that it’s staying wet or too moist for too long, then it’s time to evaluate how much water the tree is getting and how you can improve the soil’s drainage. Finally, testing the soil’s pH and supplementing with a low nitrogen fertilizer can provide your cherry tree with the nutrients it needs to grow and outlast any potential diseases or conditions.
Lastly, a good way to help limit pests and disease is to plant companion plants around your cherry trees. For a list of these plants, check out my recent post on 10 companion plants for cherry trees.