We've had this concrete floor in our front yard for a few years already, and it was getting really, really hot over the course of a day. We thought about making a garden over there for cooling purposes, and boy, what a difference.
Some sketch studies about colors, different arrangements and sizes.
Before (jan. 2014)
Execution (feb. 2014)
And the final result, about two months after everything was planted:
Some of these plants were recycled from my backyard, and some were gathered around. (Some of these aren't really appreciated, as they grow everywhere).
(Notice how the red flowered plant had such a colorful explosion after that). :D