The best time to prune trees is in late winter after the deepest hard freezes when the tree is still dormant but before the buds start to open with rapid spring growth flush, at any other time there is a chance of many problems. Some trees, such as maples and birches, tend to "bleed" if pruned in late winter or early in the spring. It may be unsightly, but it is of little consequence to the tree. It is good pruning when the tree is dormant because you can easily visualize the structure of the tree, to maximize wound closure in the growing season after pruning, and to reduce the chance of transmitting disease.

Hey Tom. Everybody around here prunes the peaches and cherries last, after apples, pears, etc. The reason for pruning Prunus last (sometimes when blooms are open), is that the rule is to prune only when the tree is growing so it can cover the wound as fast as possible. An open wound invites trouble because as you say, these trees are prone to a multitude of pests. The last few years have seen more small orchards (25-50 acres) prune after petal opening and take the prunings to market. Open Prunus blooms on the long whip growth sell. The old rule was to prune after any hard frost could occur because the frost can damage the cut bark. (Prunus are thin barked trees.) This leads to May pruning, and the orchards are too busy in May to do pruning unless you have a good crew. With the explosion of farm markets, you prune the Apricots first (March) because they wake up first. By the time your late peaches are pruned, spring is full blown. That's here in the Mid-Atlantic. Things farther north could be different, but winter pruning is not recommended for Prunus here. I found this link from Penn State. Pruning is down about 1/2way. http://pubs.cas.psu.edu/freepubs/pdfs/ua429.pdf

It certainly depends on the type of tree. And we have a lot of new rules about pruning, including when. When it comes to most deciduous trees, including fruit trees, pruning during the growing season (spring into summer) is the best way to shape and keep the trees in bounds and at the right size. For serious limb removal, we wait until they're dormant (winter). For evergreens, it's about the same -- during the growing season to shape, size and fix. The down time for evergreens varies so it's hard to generalize about when to do anything serious. Joe

Pruning of the varieties you've mentioned really should only be done to facilitate the shape of the tree and to remove dead or diseased wood. I'd also bear in mind the need to open the tree to ensure good air circulation and ease to fruit picking. I would do it all in winter when the tree is bare being mindful that you may also sacrifice some the next season's fruit bearing wood, but it can be done any time. You also need to consider the fruit load the tree can happily carry, for example, old Pete Cundall on Gardening Aus. advised you should never allow a lemon (or other citrus) to bear pickable fruit before it is 5 years old. I think that advise is applicable to all fruit trees, although at 4 years I've allowed my Washington Naval orange to provide a few very nice oranges. B.