I have a few speciments of Acer pseudoplatanus and Acer platanoides. I want to grow them, so they will have trunk without branches in bottom part and nice round "ball" at the top as that is often in urban landscape in cities.
I don't know when and how much should I trim them, so I ask you. Should I wait till the end of the growth period to trim new branches or do it now? I want tree to be about 2 meter high, a little more than ordinary human. I am located in continental Europe, so now we have growth period.
I added a photo how it looks like and another one what should it look like. The first image is one of my trees and the second image is the shape I want in the future.