Glycerin is a colorless and odorless liquid that is used in food preservation and as a sweetener. The liquid can also be mixed with water to preserve flowers as it is able to pull water out of the stem. Flowers should be collected at the peak of their blooming period as these dry the easiest. Glycerin will cause some plant foliage to remain pliable once it is dried so it can be bent or shaped for display.
Collect flowers stems that are no more than 18 inches long. The flower blossoms should be in their prime and free of tears, spots or insect damage.
Mix a glycerin solution of two parts water and one part glycerin. Heat the water to a point just before boiling and add the glycerin.
Remove the foliage from the lower 4 to 6 inches of stem while the glycerin solution is cooling slightly. Crush the stem with a hammer to increase the absorption rate. Pull back the bark on woody stems before crushing.
Pour 4 to 6 inches of warm glycerin solution into a glass vase or container tall enough to hold the stems. Mark the top of solution level on the outside of the container. Stick the stems into the solution while it is still warm as this will produce faster results.
Add more glycerin solution to the container as it disappears into the stem. The stems will take two to six weeks to completely preserve with glycerin. The flower is preserved once the stem and foliage turn brown.