Harvest the leaves to be preserved by using garden pruners to snip them off as close to the branch as possible the morning before beginning the preservation process.
Prepare the preservation mixture by heating water to 160 to 180 degrees Fahrenheit, then adding glycerine into the water at a ratio of two parts water to one part glycerine.
Remove the mixture from heat, stir it until the temperature cools to 80 to 100 degrees Fahrenheit and pour it into a flat container that is least 3 inches high and broad enough to accommodate the amount of leaves that are to be preserved.
Lay the leaves down flat in the liquid covered by at least an inch of the preservation mixture.
Allow the leaves to soak in the preservation mixture for four weeks while checking the level of the mixture each day to make certain it is covering the leaves.
Remove from the preservation mixture and allow to air-dry.