To keep your rose wedding bouquets from losing stems down the aisle, consider using a floral adhesive called Floralock. This product is used AFTER you are finished with the total design. It's difficult to insert more flowers after using stem adhesive.
Shake the can thoroughly to aerate the adhesive. Carefully slide the nozzle deep into the bouquet and squirt in short bursts. Allow to dry and then do again.
Stems will not slide out of the foam with this around the stems.
Do not overdo or you'll have dripping glue run down over your bouquet holder.