If tulips are placed in the sun, their stems can begin to twist and turn. There is no way to stop this or straighten the stems. Use caution when handling, though, because the pollen from the bloom will stain clothes. French tulips have large heads, longer stems and bend naturally. These are the most expensive variety of tulips.
Dutch tulips are the most common variety, and greenhouse tulips are the least expensive tulips.
To harden the tulip, re-cut the ends of the tulips and keep them wrapped in the cellophane in which they are sold for a short while. Do not put tulips in the refrigerator to prolong their life. Foods such as fruit will kill the tulips.