When to prune a tree?

[Rich Hebner]

I have a 15 year old Silver Maple that needs to have its lower branches cut to increase the headroom underneath. When is the best time of year to do this?

many thanks,

[Cereoid-UR12-]

Do it now.

Silver maples are nasty weed trees and you would be better off growing something that will not become a problem to keep under control. You have been warned.

[paghat]

Pruning a larger tree has so many ramifcations, you should grab a book from the library or review the guidelines published by the International Society of Arborculture. You need to know a LOT more than "when is the best time" to do it right, or you will end up permanently harming the beauty of a tree.

I have underlimbed larger trees to have airiness for shade-gardens underneath, & for so long as the upper branches are thick &amp pleasant & the tree really can look nice with a lower stretch of trunk completely bared, it's harder to screw up than when pruning upper branches of a largish tree. Even for that, though, you should at least read a good chapter in a general gardening manual on pruning techniques, as even the angle of the cut is important, & not easily described without illustrations.

Trees such as maples & birches that bleed a great deal if pruned in early spring are better pruned very late in spring or early summer when sap is not flowing so dramatically. Second-best time of year is about January before sap flow is again heavy. Third best time of year is very late in autumn or early winter when the tree is quiescent, but it will not heal well until spring, so would be somewhat at risk of disease or insect reaching the cut which will be raw for a longer time.

Early summer is also best if one wants limbs completely removed flat to trunk to heal over, as for permanent underlimbing; whereas late winter trims are "rejuvenation-inducing" & would be more apt to cause new growth. Late spring/early summer pruning is "structural." The main thing though is don't do it when sap is flowing in spring, &amp also the hottest time of summer is not good because heat already stresses the trees.

But again, UseNet advice can be mediocre at best, or even completely wrong for your zone, species, or conditions, so do check out a pruning book or book chapter from the library, paying especially attention to advice on large rapid-growth maples; advice will be totally different for fruiting trees or evergreens or for deciduous trees without profuse amounts of flowing sap.

-paghat the ratgirl

[Phisherman]

When the tree is dormant.

[John Bachman]

Why is waiting that long appropriate? It seems to me that the sap would be running then and would leak from the wound attracting insects.

John

[Beecrofter]

Bad timing for maples in general they bleed all down the trunk when spring pruned. If you must cut them for head room now leave stubs a foot or two long and then remove them just outside the branch collar in Summer. That way you don't mar the trunk with sap and when you make the cleanup cuts in summer the branch collar can make the bark to heal the wounds.