Slow leaf-out on some fruit trees
It has been a pretty good winter for the orchard, only lost one small tree to gophers, and almost no winter die back on the trees. There is however one thing which I've noticed and been puzzled about: some trees are very slow to leaf out, and when they do, they start slowly with a few branches at the bottom and work their way to the top.
I have seen this with several fruit varieties (apple, pear, plum). The tree just sits there doing nothing while most of its fellow trees have leafed out and are in bloom. Eventually these trees start swelling some buds and slowly over a few weeks leaf out fully and even bloom (the older ones at least).
I am just wondering what significance this may have. The trees are not stunted or damaged in any visible way. And perhaps this is even a useful trait, as it would protect against a late frost if some of the buds were still dormant (hasn't been needed this year but could come in handy).
Anyone have any idea as to what might cause this behavior?