Regards to the design of the flowers that I'm going to use for my garden, I have decided to go with something a little more stylised. Phil suggested looking at making the flowers simple in design but recognisable for what they actually are. An example he gave was the work of printmaker Angie Lewin.
Here are a few examples of stylised flowers I've come up with so far. The first two images are of plants called Alliums and the second two are of Roses: