Roses can be preserved by drying, freeze-drying, coating them in silica or glycerine, and boiling. To dry a rose, hang it upside down before the petals begin to wilt and fall off. For a rose that has already started wilting, place the stem in boiling water for 30 seconds, and then cut the stem before placing it in cool water.
Before a rose begins to wilt, it can be soaked in silica gel. The gel preserves the shape and color of the flower but becomes hard when it dries. Silica gel removes the scent of the flower.
To preserve the rose and maintain its delicate physiology, soak the bloom in glycerine and allow it to dry. The glycerine preserves the rose but doesn't remove its smell or harden it.
A rose can be freeze-dried by a professional using a special freezer that removes the moisture from the flower. Freeze-drying keeps the rose in approximately the same shape it was in, including preserving color and scent.
The rose's petals can also be removed and preserved for potpourri or other uses by removing them from the flower before they begin to wilt. To dry the petals, they should be laid in a single layer on a paper towel or drying rack until the moisture evaporates from them.