We have a blue spruce next to our house. It's probably as tall as I want it (I would guess 12 feet, basically reaching our roof line) and certainly as wide as I want it. Can I trim this tree to keep it from growing? If so, how would i go about this?
You can certainly try to, but you will face at least two significant problems:
- Apical dominance - if you cut out the leader (the strongest shoot right at the top of the tree) this will trigger other shoots to try to take over the job of stretching upwards. Several shoots might try to become the leader, but there will be a constant stretch upwards so it is a job that will have to be repeated
- The shape or form of the tree - blue spruces are naturally conical trees and when grown in their own right can be a beautiful sight. You can endeavour to trim the tree all over to retain the conical shape but it will be a real challenge to make it look as even as if it were left alone. In the worst case you might end up with a square shape from a distance (with multiple pruned out leaders at the top causing spreading sideways instead of reaching up) and a rough cylinder up close.
An alternative to interfering with the top growth is to look into cutting off some of the nutrient supply from the roots with careful root pruning. If it has sent out roots into a lawn area and you fertilize the lawn, cut down on the fertilizer.
In the most fortunate of circumstances, the person who planted the tree will have chosen a cultivar that tops out exactly where you need it to stop, in which case stand back and enjoy.
I'm sure this post will make landscape professionals shiver, but I have personally seen two Blue Spruces maintained at a height of about 8' without losing their conical shape for 25 years. When I was a kid, my father had two Blue Spruces in the yard, he treated them like a hedge, sheared them like privets and maintained their shape.
I would certainly never buy a conifer with that intent, but I can say with certainty that for 25 years it worked.... to the end, they never lost their shape. He just decided to replace them with some other shrubs just to change up the landscape.
This practice did not work at all with white pines.. when the leader was removed and the lateral branches were tipped back, the resulting branching was very irregular, with many branches growing inward and in all directons... in general it was a big mess. Although, in a way it was a success, it convinced him to remove the white pine, it definitely didn't belong next to a house on a 50'x100' lot. If it wasn't removed back 20 years ago, I'm sure it would be 80' tall now and dropping large limbs on the house every time there is a decent storm.