Though spring is still several weeks away, impatient home gardeners can enjoy an early taste of spring by forcing cut branches of many spring-flowering trees and shrubs indoors. Forsythia, flowering quince, pussywillow, crabapple, serviceberry, magnolia, redbud, and fruit trees can be forced indoors during the winter months.
Forcing can be done as soon as the plant overcomes its dormancy (cold temperature) requirement. This may be as early as mid-January for forsythia and pussywillow. It's best to wait until early March for more difficult-to-force ornamentals, such as crabapple, magnolia, and redbud. When gathering plant material, select branches that are at least 12 inches long and contain numerous large, plump buds. (Flower buds are usually larger and rounder than leaf buds.) If possible, collect the branches on a warm, winter day. If the plant material is frozen when collected, submerge the branches in a tub or pail of tepid water for a few hours. Later, set the branches in a tall container of water and place them in a dimly lighted, cool (60 to 65 degrees F) location. Spray or mist the branches several times a day to prevent the buds from drying out. Also, change the water in the container daily. When the flowers begin to open, move the branches to a bright room. Keep the branches out of direct sunlight and in a cool location to prolong the bloom period.
The time period required to force branches into bloom depends upon the plant species and the collection date. Forsythia and pussywillow generally take only 1 to 3 weeks to force. Magnolia branches may take 3 to 5 weeks. The closer it is to their outdoor flowering time, the less time it will take to force cut branches indoors.
This article originally appeared in the February 6, 1998 issue, p. 9.