The property behind us has a row of mature arborvitae 12'-15' tall along their property line with us. We have a 4' chain link fence around our backyard,

A couple of years ago, we trimmed back the bottom of the arborvitae on the side facing us up to 5'-6' because the arborvitae had grown into the fence, much of it dying, and we wanted to clean it up, and repair and paint our fence.

I am now considering cutting back these arborvitae most/all the way up to match the bottom, along the fence. Because of the way the sun goes, this will also allow more sunlight into the lawn and the garden area at the back of our yard.

What are the chances that if I do that, there will be green regrowth up the tree at some point? Or, is there a decent chance that the health of the trees will be affected negatively? Thanks.

 

When the trees are that big I haven't seen much new growth from the trunk. So, if you cut the branches off at the trunk there is a good chance it will mostly stay that way. If you want regrowth I would leave the branches and cut them so there is at least one live bud/leaf remaining. With at least one bud/leaf left on the branch they seem to regrow reasonably well.

 

There is some minor regrowth on the bottom portions of the trees where we cut back a couple of years ago, both off of the trunks directly, and off of the branch stubs that were cut back to within inches of the trunk. One limiting factor there, I think, is that the upper portion of the trees that wasn't cut overhangs the bottom by 3-4 feet, and blocks out sun. I was wondering if this might all improve if I cut the whole side of the trees facing us back. I would be counting on the other side of the trees facing the neighbor's house and the tree tops to have the leaves to sustain the tree.

If I do this, I was thinking of planting some vine plants (maybe like morning glories) that would climb the trees and provide some green if and until there is regrowth.

 

if they aren't your trees, there is no way I would be trimming them! And if you do, get written permission first! That being said, I think cutting them 5 or 6 ft tall would probably kill them.

 

I am not cutting the tree tops, although I think the actual tops were cut many years ago, limiting vertical growth. I am not reducing the height of the trees. I am cutting back the side of trees facing us. They are overhanging our property. And due to the legal setback of the fence, we actually own a small distance on the other side of the fence. But I certainly don't want to harm the trees.

 

I would not cut just one side of the tree. If you are anywhere that gets winter weather a wet, heavy snow or icing could seriously unbalance the trees and bring them down or put a serious bend or lean into them. I also would NOT plant morning glory. They are an invasive plant. Once you have them they are difficult to control and impossible to get rid of. There are many other flowering vines that could provide better screening, flowers and not be aggressively invasive. I'm thinking clematis might be a better choice.

 

That's a consideration, although these trees are mature and a snow/ice event that bad only happens once every few years here.
OK, thanks. I knew they were aggressive, But I did not know that they were invasive or could get out of hand.
OK, will look into it and other suggestions appreciated.

 

OP here... I did not touch these arborvitae this year, but I did decide that I want to heavily prune them back. Ideally, I should wait until winter (dormancy), but would it really matter if I did it now with my fall cleanup? (I am outside Philadelphia). Would cutting back trigger regrowth this late, and even if it did, would that be that much of a problem? Thanks.

 

I generally do heavy pruning in late winter/early spring right before they start growing in the new season. I don't prune heavy in late fall because I don't want all those fresh wounds through winter. If you cut in early spring the plant will be waking up and growing vigorously and can hopefully heal before disease finds the cuts. But, in reality arborvitae are pretty tough and can tolerate a lot of abuse.

 

I vote for no pruning at all. Try Akebia, 3 leaf or 5 leaf vines, to cover up your fence or trees.

 

Yeah, I think I will wait. There is no compelling reason to do it now other than to get it out of the way while I am doing fall cleanup. Thanks.

 

There is some type of ivy in with the trees. In addition to having cut back the lower portion of the arborvitae from the fence and opening it up a couple of years ago, I also threw down some fertilizer late last year. The ivy has noticeably spread under the trees this year and has climbed a few of them. You can't tell by the pictures, but cutting back the upper portion of the arborvitae facing us will let in significantly more sunlight for six months of the year. The hope is that this will spur some regrowth of the arborvitae, help the ivy and our lawn, and just create a trimmed, uniform wall of green facing us.

 

Pilot Dane answered this 7 months ago... Arborvidae along with most other conifers like pine and spruce simply do not regrow much new growth from the lower portion of the tree. There may be a scraggly branch here or there, but it will NEVER fill in full and lush like the top is. You are hoping for the impossible.

Anyone who wants a canopy that blocks the lowest 4 feet with greenery needs to replace the old aging trees with new younger trees that are full and lush, and tightly spaced... or come up with a new plan. Because the tree is not going to grow back.

 

The purpose of resurrecting this thread recently was that the decision was made to go ahead and heavily prune the trees back anyway, but was asking how advisable it would be to do so now vs. when the trees go into winter dormancy. I then decided that there is really no reason to take any risk by cutting them back now, and to just wait.
Of course not.
Again, I am simply going to cut back the top of the trees facing us to match the way the bottom part of the trees has been cut back. Six months of the year, that will allow more sun on our side of these trees. which MAY allow some MINOR green regrowth from tree, encourage the ivy to continue to spread among the arborvitae, help our lawn under those trees, and help a garden that is about 6' away from those trees at the one end of our yard. God willing, we will find out what happens....