You may have heard of glycerin. It’s an old-fashioned ingredient in hand lotions (rosewater and glycerin). You can still buy small bottles of it at drug stores. You can preserve all sorts of foliage with it (from oak leaves to ferns) and even a few flowers, notably hydrangeas. The plants turn color somewhat, but these are usually pleasing shades.
Prepare your foliage by stripping the bark from the thick lower stems (or mashing them slightly). Dilute the glycerin with water — one part glycerin to two parts water. Bring the solution almost to a boil (have your parents help you here) and pour 4-6 inches of it into a container tall enough to support the foliage. Place your greenery in the solution and leave it in a cool, dark place until the leaves being to turn color.
Check the plants regularly to see that there is enough solution in the container and to monitor how the conversion is going. If plants are left too long in glycerin, mildew might set in. The leaves should feel slightly greasy, but there shouldn’t be oil beads on the surface of the leaves. If the tops of your branches droop, hang the plants upside down to let the glycerin soak down to the very tips of the leaves.
Wipe the leaves with a tissue and arrange them in a vase. Lovely!
[Image: Courtesy of Flickr user crystalcolby]