Hoping this will be of some use for some people wanting something different to the traditional flowers.
Firstly, you will need to collect alot of buttons in your colour scheme. Ebay, junk shops, chairty shops, carboots, fabric shops etc will be your best friend! I am also using lace and pearls/beads for mine, aswell as various brooches. I have found that taking apart a cheap flower garland from Asda leaves white fabric flower shapes which work quite well at the bottom of some of the button flowers.
The button flower stems are florist wire, it comes in a range of colours including white, I don't intend on having mine showing when the bouquet is finished. It comes in different sizes. I used 12 inch/20 swg wire. It's easily manipulated and not too thick to fit buttons and beads onto. It's fairly inexpensive, again, Ebay is your best bet.
Hope this helps some DIY Brides-to-be!
Nat x