Now would be a great time to do some initial shaping. The spring is moving into summer and the elm will have several months of good growth ahead.
This is a little tricky though, as the trimming that needs to be done would be considered a first styling: You need to decide what you want the final tree to look like. You need to decide which branch is the main trunk for your tree, and which are secundary to this.
As a guiding principle when trimming:
- Only 1 branch on the trunk at a given point, and ideally, at a given height
- Branches split in 2. Not in 3,4, 5.. So every point where a branch splits in more than two, all others are removed
- Branches always grow away from the trunk. Branches that grow back into the tree should be trimmed
- The whole tree should have a similar "rythm". Branches at a similar angle to the trunk, flowing outwards
Here is a tree of mine in winter, where you can see most of these elements quite clearly. The one thing I did not do is not have branches at the same level on the trunk, as in this case that would have left too few branches. This is also important to realize: None of the above are fixed rules, but more guidelines to help you find your way. In the end, the tree just needs to look good and come across as realistic...