It could be darling to hand her your bouquet instead of the maid of honor. Try putting two large arrangements in vases on pedestals on either side of the bride and groom at the ceremony. If you color coordinate the arrangements to your bouquet, you could place your bouquet on one of the pedestals, show casing it throughout your ceremony. Your arrangements should also have some other colors in them so that they stand out from the dresses and add some sparkle to the ambiance. Maybe some yellows or cream colored flowers could be added.
Roses are always a good standby an come in many colors.
If you are getting married Early to mid August you could use some burgundy colored Snap Dragons. If you are having your dresses designed for you, ask your seamstress to make ribbons out of any extra material from the dresses. You could wrap the bouquets with the matching ribbon. If the dresses are already made, then go to a ribbon store with a sample of the material from the dresses in hand and try to match it. I am getting married next Halloween but have started looking into silk flowers that are on sale now.