I always soak every bridal bouquet holder in water that has been treated with Floralife flower food. If you plan on doing your own wedding flowers, be sure to treat them the same way a professional florist would.
The great part about the bouquet handle is that the aluminium decorative wire is not harmed by water.
Give the large foam head plenty of time to absorb the amount of water it takes to be totally soaked. Fresh flowers need a continual water source. If you design a couple days in advance, you'll want to keep dribbling more treated water into the foam as the flowers draw the water out.