Our mature plum tree has numerous branches where the leaves look partly 'scorched' (i.e. dry brown patches). They feel quite brittle and curl up a bit. On the other hand, the leaves on some of the branches are fine.
It was the same last year so we tried giving it some TLC. We pruned the tree last June and gave it some blood, fish & bone as well as mulch this April. Any ideas what is causing the leaves to look poorly?