It is very important to keep the flowers always at constant cool temperatures. Refrigerating blooms are allowed only if fridges are turned down low and flowers are placed as far as possible from the freezing compartments. Foods and fruits should be cleared away as they emit ethylene gas that is harmful to the flowers.
When roses are used, their stems should be supported with wire and the heads need to be sprayed with water as often as possible, and never leave roses in hot temperatures. All bouquets should stay in water when not needed, especially when the photographers are yet to arrive, and photography of bouquets should be done first thing in the morning as it is hard to keep them looking fresh the whole day, especially during summer.
Another option is to have two bouquets for the bride. This comes in handy when the ceremony is in the morning and the reception does not start until evening.