Re-cut the stems at an angle removing at least an inch of the stem. Always use a sharp knife or clippers rather than scissors as this will avoid crushing the stem and therefore the vascular system. The slanted cut opens more stem area for hydration and prevents the end of the stem from resting directly on the bottom of the vase impeding water flow.
Leaves that will be below the water line in the container must be removed. Leaves sitting in water will deteriorate and rot. Decaying leaves make a good medium for bacteria and fungi, which will plug the vascular system preventing hydration and eventually causing death of the flowers. DO NOT remove all leaves along the stem length, the flowers require the leaves as part of their hydration process. Always be "gentle" during the removal of leaves, gashes or breaks in the stem surface are "open wounds" where bacteria may enter. Try using a soft, but impenetrable glove for the removal of rose thorns and foliage.
Last but not least Check the water level daily and replenish as needed. If the water becomes cloudy, it should be completely exchanged for fresh water . As the water level gets low, you should re-fill vases with fresh solution made with correct proportions of Fresh Flower Food and water. If you do not have any additional flower food solution, at least use fresh room temperature water.
Always keep your fresh flowers away from a heat source and out of a hot sunny window.
The New York Gardener / blog