Don't let this autumn's exuberant show of colour become a fleeting memory--bring some fall foliage indoors and keep it fresh using glycerine. Glycerine, also called glycerol, is a colourless, odourless, thick liquid that is available from drugstores. Leaves that are allowed to absorb a solution made from glycerine and water will stay fresh and flexible because the glycerine takes the place of the natural moisture inside the leaf. Once preserved with glycerine, you can use the leaves in any number of crafts, including wreaths, centrepieces and garlands.
Prune several small branches from trees using a hacksaw or pruning shears. Choose branches that won't affect the growth pattern of the tree and have many leaves on them. Prune branches at night or in the morning and after a dry spell. Make sure you prune the branches before the first frost.
Crush the branches with a hammer for a distance of four to six inches from the cut end. This will help the branch's vascular system absorb the glycerine solution.
Make a mixture of one part glycerine to two parts water. For best results, test the acidity of the water using a pH testing kit. A pH of 3 or 4 is ideal. If the pH is higher than 4, add some lemon juice to the water. If the pH is lower than 3, add some powdered lime. Retest the water to ensure it is the proper pH. Make enough of the mixture so that, when it is added to the bucket or milk carton, it will cover the crushed ends of the branches.
Add 4 to 5 drops of a surfactant to the mixture to aid in the absorption of the glycerine. You can purchase a surfactant, such as Spreader Sticker, at most garden centres.
Pour the glycerine mixture into the bucket or milk carton.
Add the branches, cut-side down, to the glycerine mixture. Keep the container of leaves in a well-ventilated location out of direct sunlight.
Check the level of the glycerine solution daily and add water, if required, to ensure the crushed part of the branches remains covered.
Check whether the leaves are ready. Leaves will have changed colour uniformly and feel supple when they have drawn up enough glycerine. This could take as little as five days or as long as six weeks, depending on the type of leaves you are preserving. Magnolia branches, for example, must be immersed for three to six weeks.
Remove the leaves from the branches and use as desired.
The leaves of different species of trees will retain their fall colour to different degrees. Beech leaves and most red-coloured leaves, for example, will generally turn brown. Most yellow leaves will become more intense in colour. Green magnolia leaves will stay glossy but will turn a chestnut colour. Experiment with different tree types to determine your favourites. You can also try adding coloured dyes to the glycerine mixture to enhance leaf colour.