Air can enter the water-conducting passages through the injuries and restrict water uptake. Bacteria in the water can clog stems. While holding the stems under water or running water, cut about one inch off each stem with a sharp knife or shears. Do not let the newly cut end dry off before transferring it to the arrangement or other container. Water in which a good floral preservative has been added is the best solution in which to arrange fresh-cut roses.
Florists can provide small packages of floral preservative.
Use it as recommended to provide additional days of vase life. Do not use stronger solution than the manufacturer's recommendation. Avoid using water from a water softener. If a florist's porous foam material is used in assembling the arrangement, it is important that it is thoroughly saturated in advance in water containing a floral preservative. Use a vase large enough to keep the entire block of foam submerged.