Sanitation, along with the preservative, will help prevent bacteria growth in the water. To help keep the water fresh, remove the lower leaves from the stems. Foliage in the water will quickly decompose and allow bacteria to grow. You should also change the water in the container on a regular basis to keep it as fresh as possible. After the flowers have been arranged in their container, keep them as cool as possible.
Heat takes moisture from the leaves and flowers.
With no root system to sustain the flow of water, the flowers will wilt quickly under high temperatures. Unfortunately, display areas are considerably warmer. To extend the life of flowers, consider putting the display into cool storage during the evening or at times when no one is home. Certain storage conditions, however, can shorten the life of cut flowers. Avoid putting cut flowers into an enclosed area where fruits and vegetables are stored.