One of the memories that I have from childhood and adolescence is climbing up into the second floor of our barn—it didn’t have a real loft—and seeing bunches of flowers hanging upside down along wires stretched between the roof beams. At some point in the 1970s my mother began growing flowers that were grown to be dried, as opposed to be cut and displayed fresh.
I think that she had joined a garden club and had gotten into flower arranging. In the absence of a greenhouse to grow fresh flowers through the winter, one resorted to arranging dried flowers. One of the most popular species is statice (Limomium sinuatum) or “sea lavender,” which has small flowers surrounded by colorful bracts. When dried the crepe paper-like bracts persist and largely hold their color. Statice is relatively easy to grow, begins flower in the spring and keeps flowering until the frost kills it, and can be grown as an annual in Zones 2 through 7.
Other popular species that dry well include baby’s breath (Gypsophila), cockscomb (Celosia), amaranth (Amaranthus), salvia (Salvia), and goldenrod (Solidago). The simplest way to dry all of these is to hang them upside down in a dry, dark, well-ventilated place like my mother did. Humid places should be avoided, as the plants are likely to get moldy.
If you have taken a botany course, then you are perhaps already aware of pressing flowers in order to preserve them for a herbarium collection. Nearly any flower can be dried in this manner, although many do not retain much color and all are, of course, flattened. Alternating layers of flowers and newsprint are stacked between two boards and weighted down with a heavy object. It takes about a month to dry them in this manner.
Any plant can also be dried by submerging it in two parts water and one part glycerine (antifreeze actually works). Fresh flowers are submerged for two or three weeks and then hung upside down to drive the glycerine to the extremities of the vegetation.
Silica gel will also dehydrate flowers. Packets of this substance are often found in packages that have been shipped long distance. It can be bought at most garden stores. Flowers must be buried in a closed container. Flowers dried by silica gel may rehydrate and wilt if they are not kept in a closed container after initial drying.
Any flower that is cut to be dried should be picked later in the day when the dew has evaporated from it. They should be bound together in bunch with a rubber band and placed in a cool, dark place immediately. It is best to pick flowers before they are fully open, as they will continue to mature after they are cut and before they are fully dried.
Flowers fade because the pigments in them oxidize in the presence of light and water. Drying them in the dark prevents oxidation and thus preserves the color. Subsequent fading of the color in the dried flower is caused by partial rehydration from moisture in the air, which allows the oxidation reaction to go forward.
Hydrangeas (also known as hortensia) are woody plants that produce beautiful dried blooms. Hydrangea flowers should be allowed to partially dry while still on the shrub. They are initially green, but as they dry, they turn blue (acidic soils) pink, or purple (alkaline soils).
Hydrangea flowers are either “mopheads” or “lacecaps”. The former are round panicles and the latter are flatter corymbs. Often the lacecap flower heads will have smaller, radially symmetrical blooms at the center and larger sterile asymmetrical bracts around the perimeter.
Hydrangeas do not need to be hung upside down to dry. They will dry even if they are put in a vase filled with water.å