My weeping cherry tree is 3-4 years old. It's blooming now but has a large section of growth shooting straight up in the air. That section is covered in leaves but it never flowered. Should it be pruned during the dormant phase?
I think you have a case of a "reverting" weeping cherry.
This means as if you cherry wants to go back to its non-weeping form. This is not uncommon with weeping cherries. Here are some links describing similar cases:
If you don't do anything, the straight part will most likely become a dominant part, and you must remove it - completely.
If it was just a smallish branch, I would advice you to remove it immediately, no matter what the time of the year is. However, this a fairly large composite branch, and it may be better to wait for late fall/winter/early spring, and remove it at that time. That way, the shock for the tree will be much smaller.
And, please, make the cut as clean as possible. Pay really good attention to the place of the cut, and definitely apply so-called three-cut technique. Here is a step-by-step overview of three-cut technique:
- Prepare your tool
- (CUT 1) Make the undercut
- (CUT 2) Remove the branch (except the stub)
- Locate the branch collar and decide on the main cut place/orientation
- (CUT 3) Remove the stub.