Keep the vase filled (or floral foam soaked) with water containing a flower food provided by your florist. Flower foods make flowers last longer but it is important to follow the mixing directions on the flower food packet. Most packets are to be mixed with either a pint or a quart of water. Flower foods should not be diluted with more water than is specified on the packet. If the flower food solution becomes cloudy, replace it entirely with properly mixed flower food solution. If possible, re-cut stems by removing one to two inches with a sharp knife. Be sure to use a sharp knife or clippers that will not crush the stems. Immediately place the stems into solution.
Keep flowers in a cool spot (65 to 72 degrees Fahrenheit), away from direct sunlight, heating or cooling vents, directly under ceiling fans, or on top of televisions or radiators. (Appliances like televisions give off heat, which causes flowers to dehydrate.) Most flowers will last longer under cool conditions.
If your roses arrived in plastic water tubes, remove them before arranging. Remove any leaves that will be under water, taking care not to cut through or scrape the green bark. Recut stems by removing 1-2 inches with a sharp knife. Immediately after cutting, place roses in a clean, deep vase of water containing a flower food provided by your florist. Check the flower food solution daily and make sure to keep it full, clean, and fresh. If the solution becomes cloudy, replace it entirely.
Keep your roses in a cool place, out of direct sun and drafts.
Keep your flowers in a cool place until you can get them in a flower food solution. Don't forget how important it is to follow the mixing directions on the flower food packet. Fill a clean (washed with a detergent or antibacterial cleaning solution), deep vase with water and add a flower food from your florist. Remove leaves that will be below the waterline. Leaves in water will promote bacterial microbial growth that may limit water uptake by the flower. Re-cut stems by removing one to two inches with a sharp knife. Place the flowers in the vase solution you've prepared.