A simple thing like fresh-cut flowers can brighten your mood when at home or work. Prolong their cheery effect by removing any leaves that fall below the water line in your planter or vase.
Discarding leaves that would otherwise sit in the water and rot eliminates the bacteria or fungi that would thrive on those wet, rotting leaves. This keeps the vascular system of the flowers clear, keeps the water in the vase cleaner, and adds to their shelf life. You can make your flowers last even longer by adding sugar and vodka or aspirin to the water.
Cut-Flower Care [University of Illinois Extension]