All of a sudden green industry professionals and clients are noticing what seems like precipitous leaf drop on a lot of woody plants. In nearly every situation I have investigated there have been insects and/or a little disease present but these would NOT account for the earth underneath trees being littered with yellow leaves.

I don't think it is any coincidence that this leaf drop has come at the same time as the hottest weather so far in 1998 and the driest. At home in Brevard I have not had measurable rainfall in 10 days . . . the longest dry period in 1998 (54.3 in. of liquid has been emptied from my Brevard rain gauge this year).

The leaves I have seen seem to fit into two categories: (1) Evergreens, particularly hollies but some ericaceous plants as well, are dropping the leaves they would normally drop this year but most of these leaves seem to be dropping at once. All that is unusual about this leaf drop is that it is happening mostly at the same time and perhaps a little early. (2) Deciduous plants like birches are starting to drop leaves as well. Some plants respond to drought stress by dropping the oldest leaves. That is what they are supposed to do. If it stays dry a while longer, watch for black locusts and tulip poplars to follow suit. The same may happen to sycamores if there are enough sycamore leaves that aren't severely stunted by anthracnose.

There seems to be nothing to worry about. The trees I've seen are healthy. However, I wish you luck trying to convince your clients that this dramatic leaf drop is a response to moisture stress . . . I hesitate to say drought stress . . . following all the wet weather we have had this winter and spring.

Return to Richard E. Bir homepage
North Carolina State University