Zinnias grow in numerous colors and flower types to suit any floral arrangement--from a simple, elegant vase of colorful blooms to a Victorian basket of flowers. Zinnias are easy to grow, as well as easy to cut for floral displays. Use a floral preservative to keep zinnas fresh for as long as 7 to 10 days in an arrangement. Cut zinnia blooms in early morning before the heat of the day has time to wilt the stems and flowers. Choose blooms that are fully open or almost fully open with long stems. Use garden snips to cut the stems and put them in a bucket of water. Keep the cut flowers shaded since they tend to wilt in direct sun.