On Saturday, June 24, 2017 at 12:51:40 PM UTC+1, Al-T wrote:
Could anyone kindly tell me what might be happening to the leaves on my plum tree? 99% of the leaves are perforated and some are yellowing. Here is a photo:

http://tinyurl.com/yb89oz2n

The soil is fairly clayey and alkaline. I lightky dug in some bone meal early this spring.

Many thanks for any insights.
Al

PS... I should mention that I have another, younger plum tree, planted about 12 feet form the affected one, and it is not affected at all. Neither tree produced any blossom this year.

Al-T