Use a good commercial flower preservative in your water to extend life of your flowers

Use a knife to cut the bottom of the stems at an angle. Do not use scissors as they clamp the stem

Use 6-8 drops of Clorox Unscented Bleach per gallon of water

Make sure you are using a vase that has been thoroughly cleaned. All leaves should be outside of the vase to ensure that water is free of dirt and residue

Replace water every 3-4 days, or as you see the water is turning cloudy and murky. The chlorine (bleach) treatment mentioned above should be useful to eliminate the growth of bacteria in the water.