oldryder:

Apples would need to be really dry to drop leaves. Are you sure that's what's going on? The trees would quit growing well before dropping leaves. And you don't want to spur new growth at this time of year. So you may not want to water now. Just don't let them go into winter really dry.

What doesn't quite add up for me is you are talking about watering them yet they are dropping leaves? Is your soil really that droughty or are these those trees you moved this year?

AS you can tell I'm not really sure what's happening up north.

When some are still lush then I don't think it's drought.
Are all on the same rootstock?
The damage was done way back, perhaps too wet at one point standing in water for a while?

it's been dry here for about a month. soil in affected area is sandy and well drained. all are semi-dwarf but not certain if all the same rootstock since I have 5 different varieties in the area in question.. thats something I can look into.

more info - it's been dry enough for mature poplar trees (which have extensive root systems) to drop leaves. ditto for chinese elm.

mark

Are there same varieties with contrasting responses? Different varieties may react differently to water stress. At the end of the season trees are more likely to defoliate because of drought (or excess water) as you've probably observed.

If the ground under apple trees is obviously bone-dry (dig down a foot) you should go ahead and water. I believe the danger of them putting out vigorous growth that threatens their ability of hardening off is past and never much of a concern in any case. Otherwise every summer drought followed by late rain would cause a major kill off of trees- at least on years with harsh winter.

I would look to how they were planted, and EXACTLY how they are being watered. Newly planted trees the first summer need to be watered directly on the rootball as it was in the container, presuming these were planted from a container and not bare root. These you say are three years old, and if that means they were planted three years ago they should be well established in you native soil, and I would dig down and see. Al

these were bare root plantings. Also, I transplanted 1/2 dozen of the trees from the same planting this spring and was particularly interested to see if they were root bound since I have be surprised at the relatively slow growth.

anyway the trees I dug up had nicely developed root systems.

the transplanted trees are doing fine but they are in an area with a bunch of new trees (planted this year) so they've been getting watered regularly.

seems like my basic problem is I assumed 3 year old trees wouldn't need watering anymore and in at least some cases that turned out to be wrong. it's been dry here but not terrible; the corn on my land got enough rain to grow well.

Here where it does not rain from May to October, summer watering in sand based soil will be needed as long as we expect to get fruit from our trees. My property is a clay loam that allows dry farming if reduced yield is acceptable. Al

I would think if you can grow corn without irrigation you should easily be able to do the same with mulched apples. Are there large trees nearby competing for water? It is amazing how far roots can spread from established trees- their ability to extract water far exceeds that through mychorizal fungi. How large is your mulched area under the trees and is grass mowed on its edge or are large deep-rooted grasses and broadleaves allowed to flourish? Is the soil as deep where the trees are as in the corn field?

harvestman;

no competing trees. vegetation around the trees are relatively sparse and I keep them mowed to boot. mulch area around the trees is roughly 18 - 24" radius.

soil depth is a question mark; best answer I have is tree area was cornfield prior to planting the trees there.

mark

Mark, I establish trees on many different types of soil here without the help of irrigation- and these are bearing age trees much more susceptible to drought stress in their first year of establishment than are your trees. I can't say these trees are never stressed by drought, but it has never killed them.

I've never seen trees visibly stressed by lack of water under the conditions you describe, although I can't be sure of all the conditions there. I will way that I use about a 6' diameter mulched ring with around a 3-4" layer of woodchips at most sites. Your weed free rings are pretty stingy for unirrigated trees not yet fully established.

We didn't establish the root stock of trees that are affected. 111 is fairly drought resistant, M7 less so and more dwarfing rootstock much less so. M26 on down often need irrigation- especially when young.