Pretty Green Boutonnieres

Ooooh! I want some like these! I just discovered Laurie's blog through {Once Wed}, which is full of wedding inspiration and crafty projects. I think I'll go ahead and order those feathers I talked myself out of on Etsy.

Boutonnières are something I will most likely complete weeks before the wedding and leave a place for a live flower. I'm not entirely sure how to do this. Any suggestions?