Maybe the crux of this conversation about rules of design is less about,"how to" and more about "why". Some folks are keen to ascend to a mark, they compete a lot, they strive to a certain excellence, they work hard, when in their gardens they look about at objectives and creations, they get stuff done and are proud--this all is good, I suppose, but I don't really personally know, because I don't lean this way too far, it certainly is a most productive and systematic way to accomplish something.
I only know what I do. I have raised and nurtured trees, for pushing 40 years, and in my trees, I find myself caring about and noticing playful nuances, telling lines, and interesting iteration. Trees without some connection or story are a bore to me. I have bought trees a couple times and every time I regret it. The time I spend with my trees is reflective. It is a part of me, a joy, and a strife and the most ironic and herculean consumption of what little life I have left after chasing a subsistence. I have come to covet the small flourishes(like the Grouper tree), tragedies and comedies, the anomalous, and the stricken--somehow preconceived rule never are in the front of my mind. After a while, train wheels just fall off by themselves, I think.