Our River Birch Has Leaves That Are Turning Yellow And…
Gillian Asked
Our river birch has leaves that are turning yellow and falling off. Is this a diseaase or drought issue?
The Gardener’s Answer
Hello, Gillian in Kentucky: There are a few different reasons why the foliage on your river birch (Betula nigra) is turning yellow. The most common reason is a result of heat and lack of moisture. Is your tree a new planting or has it been part of the landscape for many years and has an established root system? Either way, this tree is a water lover, and this growing season has been so hot and dry that if your tree did not receive supplemental moisture, this is likely the reason for the yellow foliage. As a result of this type of stress the tree will drop some of its foliage. Chlorosis is another possibility; this iron deficiency occurs when the soil is too alkaline for the plant to take up the iron or it might just not be available at all. If the yellow leaves have green veins then chlorosis is a possibility. Thankfully, river birch does not have many insects or disease problems, but birch leaf blight is a fungal issue that can cause the foliage to develop black spots with yellow rings around them. Infected foliage will eventually turn pale yellow and fall from the tree. It is important to have the problem diagnosed so you know what treatment options you have. You can take a sample of the foliage to the Jefferson County Extension office to have the horticulture agent take a look and give you a positive diagnosis, or you can take a sample to one of the local garden centers as well. This way you will know exactly what you are dealing with and how to treat for it.
