Pruning Leyland Leylandii Cedar Cypress

Asked January 28, 2017, 11:59 AM EST

Pruning Leyland Leylandii Cedar Cypress Trees are beautiful in natural shape, providing privacy on perimeter of acre, not near structures but some are only 3' away from road. Some are up to 25' tall by 7' to 10' wide at base, about 8 years old. Longest lower branches are 12' to 15'. Should tree be pruned? I've never pruned an evergreen and after this heavy snow and rain and breakage of a few branches, I'm thinking they should be pruned. If pruning is necessary, I've read to prune to lateral but where is that on this tree? I got out yesterday and started pruning to right left branches, maybe it should be vertical and horizontal instead. Also 1/4 to 1/3 of length. Youtube videos aren't helpful. I hope not to lose too much of their feathery look. Do they recover that droopy look if pruned?

Clackamas County Oregon

2 Responses

I’m sorry to see how our recent unusually heavy snow storm affected your Leylandii cypress hedge. Because Leyland cypress is considered a weak-wooded plant, they’re considered unsuited to regions where they may be damaged by snow and/or ice. The dilemma for us in the northwest is that we seldom see such damage, much less plan for it as is done elsewhere.

Judging by the size and extent of your hedge, I suggest you invite several Certified Arborists for onsite evaluations and their opinions of what can be done. Then, hire the company you prefer. To start your project, go to www.treesaregood.org where you can search with your zipcode.

Broken branches should be removed soon. Your question about pruning to a lateral means that you should make a clean cut at a side branch which is at least half the diameter of the broken part. (In the image with the close-up view of the broken tip, the cut would be made just this side of a pair of side branches.)

I also suggest you consider waiting for weeks, possibly months, before any additional pruning is completed. The reason is that some of the bent branches may return to a suitable position on their own.

And please don’t apply pruning paint or other so-called sealers to the pruning wounds.

Theses resources may provide useful information, including a few precautions you may be able to use in the future:

- “Caring for ice-damaged trees” also applies to snow-damaged trees: https://forestry.ca.uky.edu/files/caring_for_trees_damaged_by_ice.pdf

- “Prepare your landscape for snow” https://chatham.ces.ncsu.edu/2015/02/preparing-your-landscape-for-snow/

- “Pruning trees”: The first illustration on this page shows how you might prune a damaged cypress: Identify broken, or dead, branches and then remove them at the trunk. (Cypress branches won’t sprout if the stub lacks green needles.) https://chatham.ces.ncsu.edu/2015/02/preparing-your-landscape-for-snow/

- “Ice-damaged trees” can also be used for trees weighed down by heavy snow as yours were. http://extension.illinois.edu/icedamage/

If you have additional questions, please ask when you reply to this email.





You wrote:

Thanks for answering my “ask an expert” Leylandi cedar question. I’ve not been able to respond to your answer or contact you using the site, so hope this gets to you.

I have, over the years, woven the tree branches together to provide quicker privacy. Arborist said that would make branches more supportive of each other during snows. He wants to cut them flush, except for side growing, privacy giving branches. These branches growing toward road are the ones he wants to cut flush, because they’ll never look good if individually pruned, he says. I don’t like the boring and ugly hedge look, so won’t chose him. Do you have any idea what can be done with branches growing toward road?

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I’m sorry to learn that you had difficulties replying to the response you received from Ask an Expert. Even so, congratulations on locating a work-around by emailing the OSU Extension Urban Horticulturist for the metro region OSU Master Gardener Program.

I suggest you invite as many Certified Arborists as needed for onsite evaluations until you find one who understands your requirement that you prefer this Leyland cypress hedge to retain as natural an appearance as possible. That may be difficult to manage depending upon the specifics of how these cypresses grow, the quality of their wood, as well as the kind and severity of damage they sustained. In the end, because of the restricted space – especially on the road side – you may need to compromise on your goal of a natural appearance.