Interesting to see. I confess to being puzzled by its ultimate purpose which I didn't realize until now was important to me. Funny how we limit ourselves.
It is touching on the complementary colour wheel, diverse angles and shapes interest. When you are judging another's work, what are you looking for, - surprise, fresh view of an old object embellished with living plant material, feeling or mood projected or does the competition category define these displays.
I read an article recently that advised that one should generally follow the rules of the art medium but deliberately break one of the rule of art for freshness.