This isn't a flower garden, it's my vegetable garden, but I don't see any reason why the same idea couldn't be used for either -- I just use my Printmaster program to insert shapes on a representation of my garden that I drew on a grid and scanned into the program. Each square is about 3 x 3 feet.
Especially if you're buying flower plants (as opposed to growing them from seeds) doing something like this would help keep from buying too many and then not having anywhere to put them. And if I didn't do it with my veg garden I'd end up growing 80 tomato plants because I wanted to try a lot of different kinds, and then couldn't fit anything else in !
