When to Prune Hemlock and Blue Spruce? - Ask Extension
Hello. I have a blue spruce (image attached) that I am looking to prune, removing the lower limbs in order to raise the canopy so it starts at 10-12 f...
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When to Prune Hemlock and Blue Spruce? #375698
Asked November 07, 2016, 12:30 PM EST
Hello. I have a blue spruce (image attached) that I am looking to prune, removing the lower limbs in order to raise the canopy so it starts at 10-12 feet, providing more light and space to navigate under the tree. I also have two hemlocks (image attached) in the front yard that have not been very well maintained. I would like to have them pruned to look similar in shape, raise the canopy of each so it starts at about 8 feet above the ground/sidewalk and maybe open up some of the canopy to create a layered, almost bonsai look.
I have been waiting until well into fall to prune, but looking at some various extension sites, they seem to suggest waiting until late winter or early spring to prune these types of trees, while "dormant" and just before evergreens start new growth.
Given that these are well established trees, do you think I can prune them back in November or early December, or should I wait until February or thereabouts? Also, do you think I can prune the hemlocks all in one session or do I need to do it over multiple seasons?
Please advise. And thank you for your time!
Shaun
Multnomah County Oregon
Expert Response
You're probably okay pruning your trees now, through February. It's best practice to do it while the tree is dormant. You should not remove more than 25% of the foliage at one time. So if lifting the canopy to 8 feet would put you over that threshold, you're best doing it gradually over a few years. I would also approach the idea of thinning out the canopy (i.e. the layered look you refer to) with extreme caution. Because most of the interior of the evergreen canopy is dead (i.e. only the tips of the branches have live foliage), the end result may not look at all as you intended. Bottom line: go ahead and prune the lower limbs, but take it slow.
For more information on pruning mature trees, here is a resource from the International Society of Arboriculture.
For more information on pruning mature trees, here is a resource from the International Society of Arboriculture.
Thank you Amy! I will proceed with patience and caution when pruning the hemlocks.
If we were to remove a few limbs to open up the canopy, exposing the dead branches, will new growth eventually sprout and fill in the dead areas?
Regards,
Shaun
If we were to remove a few limbs to open up the canopy, exposing the dead branches, will new growth eventually sprout and fill in the dead areas?
Regards,
Shaun
No, conifers won't sprout new growth in those dead areas.
