In March, an arrangement of colorful blooms can help keep the winter doldrums at bay until the outdoor gardening season begins. Although it's always nice to purchase a bouquet from a florist, branches of some spring-flowering shrubs and trees are easily encouraged or "forced" into bloom indoors. By now, the woody plants that can be easily forced have accumulated enough hours of chilling required for bloom. Depending on the plant, flower buds on cut branches can begin to bloom Â within one or more weeks with a bit of care.
Some of the easiest plants to force are willows and forsythias (Figure 1). Other ornamentals that can be forced with a bit more effort include beauty bush, crabapple, flowering quince, star magnolia, redbud, serviceberry, and witch hazel. If you haven't quite finished dormant pruning, small branches of fruit trees can be collected in late March or early April and forced indoors (Figure 2).
The first step in forcing is to identify the flower buds on the shrub or tree. Flower buds tend to be rounder and larger than buds that produce leaves. Flower buds on spring-flowering shrubs are usually found toward the end of the small branches since they were produced on last season's grow. In contrast, many of the flower buds on tree fruits are produced on two-year-old or older wood further away from the branch tips (except peach). Apple, apricot, cherry, pear, and plum flower buds are generally borne on short twigs called spurs.
If possible, cut the branches for forcing on a day when the air temperature is above freezing to better transition them into warmer indoor conditions. Use sharp hand pruners to cut 18 inch-lengths of branches. Diagonal pruning cuts help repel water and minimize later disease infection of the plant outdoors and will maximize the uptake into the cut stems when brought indoors. Take care to remove wood randomly around the shrub or tree to maintain the natural form of the plant. Branches near the exterior of the plant will likely have the best flower buds since they were well-exposed to sunlight during the past growing season.
Immediately after cutting, place the cut ends of branches in a pail with lukewarm water out of direct sunlight in a cool area indoors to begin the forcing process and to produce bloom from all the stems at nearly the same time. Let the branches soak in the pail at least overnight. Check the water every few days. When the water becomes cloudy, change it to prevent stem rot. Once the buds start to open and a bit of color from petals is visible, branches can be transferred and arranged in a vase with fresh water. To prolong the blooms, keep the vase out of direct sun, drafty areas, and away from heaters.
For a more staggered bloom, simply cut stems of outdoor plants at different times. Alternatively, branches can be cut at the same time but sealed in a plastic bag and stored a refrigerator. Later, remove the branches at different intervals and follow the forcing procedure. The longer the branches are exposed to cold temperatures, the shorter the time to bloom.
REVISED: March 4, 2021