Wash the vase before you put the flowers in it. The vase may have dirt, dust or remnants of the last flowers that were in it. Any of these items can contaminate the water and cause the roses to deteriorate quickly. Start with a clean vase that is rinsed thoroughly to remove any soap residue as well. Fill the vase with tepid or lukewarm water.
Add a preservative for flowers or a water-soluble plant food designed for roses to the vase water. Refresh the water daily with fresh plant food to help keep the flowers nourished and thriving as long as possible.
Cut the stems with a sharp knife right before placing them into the water. Cut each stem at a 45-degree angle. Do not use scissors when you cut the stems because the edges of scissors can tear the plant stems.
Place the flowers in an area out of direct sunlight. Keep the ambient temperature as cool as possible. Warm environments will cause the flowers to wilt more quickly than a cool area. Do not place the flowers in the refrigerator at any time because the temperature may be inconsistent and could cause the buds to freeze.