Have you noticed that some of your trees act like fall began early this year? Particularly cherries and poplars. Some cherries even began losing their leaves in July! It is normal for cherries and poplars to be some of the first trees to experience yellow leaves late summer, and begin dropping them – sometimes before Labor Day. But this year has been extreme. Why is that?
Color change in leaves is normal as trees prepare for dormancy and green chlorophyll stops being produced in the leaves. Chlorophyll masks the other naturally occurring leaf colors. When the chlorophyll goes away, we see the other colors: reds, oranges, yellows, etc. Cooling temperatures cause trees to enter the dormancy cycle. But other stressors can cause the same result. For instance, periods of drought, high temperatures, excessive rainfall (among others.) ALL of which we experienced this year alone! Cherries and poplars are just more susceptible to these environmental stressors.
We do need to be aware that some bacterial, fungal and insect infestations can cause leafs to yellow and drop. So if your cherry is the only cherry on your street experiencing early leaf drop, it would be good to have it assessed by an arborist. And we do need to rule out any watering issues – under or over watering. Both can stress a tree resulting in premature leaf drop.