Hanging plants to air dry is one of the oldest methods of preserving plants. Using a dry, dark corner of a garage, barn or closet works just fine. Air circulation and minimal disturbance are two things to remember; you don't want to hang your plants in high traffic areas where the plants may get knocked around. Some plants that air dry well are grasses, herbs, lavender, yarrow, roses and daisies.
To create bundles of either flowers or herbs, cut the stems at least 4-5 inches long and remove any lower leaves. Separate the plants into individual species or clump bouquets together, trying to make the bundles smaller than larger to keep the drying process even. Instead of using string, I wrap the bundles with a rubber band and use an S-shaped paper clip to hook the plants to overhead lines. The paper clips also make it easier to unhook the dried flowers.
The drying process takes about 3 weeks. Herbs can then be crumbled and saved in labeled jars, and dried flowers or grasses go into wreaths or dried floral arrangements.
This is the scientific plant collector's method for preserving specimens, but also works well in the home garden. A plant press made of alternating layers of cardboard and newspaper with ends of wood is an easy way to preserve some delicate flowers like violets and pansies. Start with a base of plywood, then alternate layers of newspaper sandwiched between cardboard. The newspaper absorbs moisture and the cardboard keeps flowers flat. When finished with the layering, add the top piece of plywood and tighten the press together with straps. The press flattens the flowers and leaves, so a little more care in arranging the flowers to avoid creases and folds has to initially be done. Also, remember to store the press in a dry location.
When dried, the flowers can be glued to cards or letters or mounted in photo frames and labeled like a 19th century plant collection.
Another great way to quick dry flowers is to bury them in silica gel crystals. This works well for plants with compact petals like roses, mallows or black-eyed Susan's. The granules absorb moisture from the flowers while retaining form and color. Available through craft stores or the Internet, the crystals need to be dried in a microwave or conventional oven, but will last indefinitely.
Depending upon the size of the flowers, place a 1-2 inch layer of crystals in the bottom of a container. Though this method works well for delicate or flat-topped flowers, even tubular flowers can be dried. Use flowers in their prime and place them flat on the crystals. For tubular flowers, fill them with granules and lay them flat atop a layer of crystals. Arrange the flowers so that there is a little bit of space between
them, and then slowly pour more crystals into the container to cover the flowers. You can layer flowers and gel in the container, but close the lid to speed up the drying process. This process takes several days. The dried flowers can be glued or wired into wreaths and arrangements.
Available from a local pharmacy, technical grade glycerin is used for thicker leaved plants like magnolia, eucalyptus, ivy, salal and birch. Use a 2:1 mixture of warm water to glycerin, and place in a vase. Clip the stems of leaves to less than 18 inches long, and remove the lower 4-6 inches of leaves. These stems should be mashed so that the stems uptake the glycerin. Place the stems in about 4-6 inches of the mixture and let stand for 2-6 weeks. The leaves may turn brown or stay green, but will remain pliable for use in arrangements or wreaths.
These methods will enable you to enjoy your garden into the winter season or to supply you with material to create beautiful winter gifts from your summer bounty.