Plum trees comprise a diverse group of species from the genus Prunus, family Rosaceae. They are of medium size and, without pruning, can reach up to 39 feet tall and spread across 33 feet. These trees blossom in different months depending on the country, and their edible fruits are related to peaches and cherries. Unfortunately, as with all plants, they also suffer from diseases and conditions that cause yellowing leaves.
Plum tree leaves turning yellow: Common reasons
Lack of water
If you notice your plum tree leaves turning yellow for no apparent reason, it could be that you are not watering the tree enough. This can happen with automatic irrigation systems. If you do not check them regularly, the drippers may become blocked resulting in insufficient water for the trees.
Check the irrigation systems regularly and make sure they are in good working condition. While these trees have moderate water needs, they should not be planted in waterlogged areas. They prefer moist soil, but make sure it is fast-draining so the water does not get trapped in the soil, which could lead to root rot.
Nutritional deficiencies
Plum tree leaves turning yellow could also be attributed to nutritional deficiencies. If the trees lack nutrients such as iron, manganese, magnesium or zinc, the leaves usually turn yellow. Certain fertilizers could also cause foliage to become thick and yellowed. Trees grown in poorly-draining soil with high alkalinity also tend to suffer from nutrient deficiencies.
Trees with iron deficiency will exhibit dying leaf edges. Manganese deficiency only targets older foliage, although young foliage may not be spared if the deficiency becomes severe. The leaves may not only turn yellow, but could also drop off prematurely.
To correct an iron deficiency, apply iron spray to the soil, preferably before new growth. Give four or five sprays for a couple of days to treat the leaves so that they become green again. See to it that the water used for the iron fertilizer is distilled so that the pH is more or less seven, which is neutral. Add a wetting agent to the iron fertilizer so the iron can penetrate the leaf’s surface.
Use fertilizers with chelated iron if your trees suffer from nutrient deficiencies. Sulfur should also be applied to the ground just outside the tree drip line. This increases the acidity of the soil so the nutrients become more accessible for the trees.
Other nutrient deficiencies that could contribute to yellowing leaves may include boron, nitrogen, potassium or phosphorus. Aside from commercial fertilizers, you can also treat the soil with organic fertilizers like composted manure and yard waste. Foliar applications made of seaweed extract or fish emulsion may also be used.
Diseases
Certain fruit tree diseases may afflict plum trees, resulting in their leaves turning yellow. These include the apple mosaic virus as well as other viral diseases. Bacterial leaf spot or shot hole disease could also afflict your trees and cause leaf drop. Cold and wet weather can aggravate certain diseases.
To solve this problem, treat the diseases with a copper fungicide. However, it cannot be used during the growing season due to phototoxicity.
Fungal diseases like Armillaria root, crown root and Verticillium wilt may also cause problems. Sanitize by raking and disposing of infected plants. Post-harvest, apply a mixture of copper sulfate and lime.
Pests
Plum leaves turning yellow may be due to spider mites or an aphid infestation. Aphids excrete honeydew, which creates a sooty mold. A strong spray of water should be enough to reduce the pest population. Oil sprays are also ideal to treat plum trees.
Can yellow leaves turn green again?
Yellowed leaves are unlikely to turn green again unless caused by a nutritional deficiency. Most plant owners agree that it is rare for yellowed leaves to turn green again, so a good option is to remove the yellowed leaves and dispose of them appropriately.
Conclusion
As with all plants, plum trees can be prone to yellowing leaves for a number of reasons. These include underwatering, diseases, pests or nutritional deficiencies.
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