The app says that I am past being able to do post leaf drop pruning and wiring, but almost none of my trees have even started to change color yet nor are there leaves almost dropping off the branches. Does that mean that I still can do it or is it too late, because winter will be approaching. I’m in zone 4b
The App is most likely based upon the “average” data. I looked up USDA zone 4b and it indicates that the average date of the first frost is Sept. 15th. That will normally initiate leaf drop so it would be too late in an average year. This is why the calendar, and an App are only a guideline, and you need to base things upon your tree’s behavior.
Since it looks like you are having a late fall so I would apply the general rule of have a week or two for this work after most of the leaves drop. However, I would do it ASAP after leaf drop and be prepared to protect the trees if your weather decides to go from nice fall to a more typical (or even early) winter.
PS I saw that some areas in the eastern United States have seen a drop of 30F (17C) in a single day to solid freezing temps. That can cause a lot of damage to the trees. If mine are not in storage when i get that type of shift I get them all of the ground, cover what I can, and spray then with water as it starts to freeze and then again a couple of times during the night (bringing the hose inside to keep it from freezing).
I questioned the apps accuracy in the spring
what Mirai said was the app was a general guideline but it could not account for micro climates, odd weather cycles etc, etc
they suggested changing the zone by one notch to more accurately match my micro climate for this year
I just shifted from zone 5 to zone 6 and it moved leaf drop prunning out by 7 days
which still may not be enough as my native sugar maple just started its color change in full swing over the weekend
play with the calendar, realize it is just a guideline and follow Marty’s advice.
good luck
Thanks, I had switched it to zone 5 and pushed it back to this past Monday. We still haven’t gotten our first frost. I have a few old elms I wanted to
bring back into shape and adjust. The previous owner had neglected them for several years and I wanted to work on them. Here are pics of them. The large one is a Chinese elm with dead wood along the one side of the trunk. The other is a cork bark elm imported from Japan. Both have been bonsai for about 40-45 years. The plan was to cut back and adjust structure this fall and repot in spring since he says neither have been repotted in the last 4-5 years.
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Keep in mind that Chinese elms (Ulmus parviflora) can be evergreen or close in warmer climates. I keep my cork bark in the cold greenhouse (just above freezing) for the winter and it often still has some leaves in the spring. I have also found that it can be cut back and wired just about any time and will respond with new shoots. I have not cut back into very old wood, but I am constantly taking off buds and shoots in very corky areas. Now if only my cork bark maple would do the same!
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Thanks Marty, as you can see in the pic. There are no shortage of sprouts on old wood with the cork bark elm. And yes, I wish other species would sprout so readily. I think I am going to air layer one of the branches off the cork bark. It needs to be thinned and two trees are better than one! I might wait until after that to style it. So maybe next fall. But the large one needs a serious cut back and adjustment of its branches.