I am having a rustic wedding, and I've already decided what I want for my flowers. My BMs will have baby's breath bouquets, and my bouquet (as well as all the centerpieces) will be wildflowers. However, I cannot afford to have real flowers, or hire a florist. Therefore, I'm doing silk flowers for my wedding, and I'll be arranging them myself.
The problem with this is, while the flowers DO come in bushes, I have to buy my flowers individually by type and/or color, and then arrange them in a mixed way to obtain that "wildflower" look. I have NO idea what flowers to buy to do this, or which colors to buy them in. For instance, peonies are a good option to throw in there, but then how do I decide which color best suits them? I know I want a really colorful bouquet. Here's a pretty great example...

Any suggestions are appreciated.

I should mention that I'm getting married in the spring.
Re: What kind of flowers should I use?