I have some trees that need to be changed to a different type of soil. They look like they were put in some kind of top soil or something. I want to change them to a decent bonsai mix. They are all collected trees that will probably start being worked on next year. One is a bald cypress, a barberry, and a trident maple. Should i just try and get through the winter, maybe aerate it, or chance changing the soil after dormant? If anyone could explain whats happening to the trees energy and roots, and why or why not you should do it, i would appreciate it.