Blue Spruce Tree
We planted a little Blue Spruce tree about 4 years ago. This year we noticed what appeared to be a 2nd top coming up on the tree. After careful inspection we've discovered that we have conjoined trees. The single trunk comes out of the ground for about 3 inches and then the 2nd tree comes off the side of the trunk. We thought we had a nice full tree and didn't realize there was a 2nd tree there until it had a big growth spurt this spring. The taller top is the original tree and the one to the left, with all the new growth on top is the 2nd one. To remove the 2nd one, we'd have to cut it off the side of the trunk with a saw. That would also leave us with a lopsided tree. My question is, is it ok to leave both trees growing together like that, or will it cause a problem as they get bigger. Thanks for you help.
Certified GKH Gardening Expert
From your description and the photo, it appears that what you have is not second tree, but one tree with a common root system, but with a "co-dominant stem" or "secondary leader"
The easiest and least disruptive for the form and appearance of the tree in the short term, is to suppress the smaller leader by lightly pruning the top and allowing the primary leader to grow uninterrupted.
A more extreme choice, as you have indicated, would be to remove the secondary stem at it's point of bifurcation from the main leader. You would have to live with the vacant side until it re-grew new foliage on that side, which could take two or three years.
If this is a full size blue spruce, the latter would be my choice, because of the potential problems and risk of structural failure (splitting apart) associated with eventual large co-dominant trunks with a tight V crotch and embedded bark.
There could be ongoing and potentially expensive pruning and cabling maintenance needed over the years.
If it's a dwarf variety, then I would probably choose the first method and just accept the slight asymmetry of the crown, and keep the second leader headed back a little and shaped as best possible to form a continuous foliar crown with one dominant central leader.