Interestingly, in the backyard, the height of the trees is not noticed, because you can see into the trees, getting a sense of depth, the tops are out of visual range unless you crane your neck to look up, and the understory is in good balance with the deck and grass. The most common imbalance in rose gardens seems to be the relationship between path and bed. The sense of imbalance usually comes from designing the paths to fit the beds rather than the plants growing in them. The larger the plants, the larger the path. This allows the visitor to step back from being overwhelmed by a tall, full bush.
Smaller plants justify smaller paths, inviting close scrutiny.
The balance at the Woodland Park Rose Garden is very good, with wide paths traveling through large beds, well defined by box hedges and beefed up with sculpted trees and rose standards. The concept of chi, or energy, is a point where controversy seems to arise. In greatly simplified terms, chi is lifeforce. Every living thing contains a spark that identifies it as alive rather than inert. Western thought acknowledges that beings receive that spark at conception, and lose it at death.