Juniper is one of the traditional trees, another is Japanese Maple. I had both juniper and maple trees while I was living in Japan. Some of my students gave me some trees that were about 15 years old when they gave them to me. I did more trimming and molding and repotted a few, but was too leary of trimming roots. From experience elsewhere I knew that you didn’t screw around with roots under the drip line without drastic effects on the tree, like killing it or killing half of it. After taking care of them for about 7 years, I returned them to my students before repatriating. It was a really calming thing to do.