Forcing Flowering Branches
After another long, cold winter, it's time for some reminders that spring is just around the corner. The winter landscape can be beautiful, but it can also drag on for what seems like an eternity. The perfect remedy to chase away the dreary winter blues and bring some spring color into your home is to force some branches from your favorite spring-blooming shrubs.
When to Harvest Branches
Almost any shrub that blooms in early spring can be forced into bloom inside. Many ornamental trees and shrubs set their flower buds during the summer for bloom the following spring, go dormant in winter and come out to bloom when exposed to warm temperatures and moisture. Late winter, the best time to prune deciduous trees and shrubs, is also the best time to cut branches for forcing. The flower buds are generally fatter and more rounded than leaf buds.
The farther into spring you collect branches, the earlier they will open. Some woody branches will take up to three weeks to bloom, while others will flower in a week or less. No matter how long it takes, this is a great way to have a few blooms indoors while you wait for the arrival of spring.
Good Forcing Techniques
It's best to cut branches for forcing when the outside temperature is above freezing – they will be more pliable and make a better transition from cold outdoor temperatures to warmer indoor temperatures. When you get inside, recut the stems by a few inches under running water to prevent air from being sucked into the vessels. Make sure you cut the stem at an angle to give the branch a larger surface to drink in the water.
After the branches are cut, hammer or split the cut ends, then submerge the branches in very warm water in the bathtub for about four hours to allow the buds to absorb water directly.
Afterwards, you can stand the cuttings in a deep bucket of warm water with a plastic bag over the tops to increase the humidity overnight. The next day, you can stand the branches in fresh warm water with a floral preservative dissolved in it and put the container in a bright location.
You should start forcing at 50 degrees Fahrenheit; higher temperatures at the start will blast the buds. After a couple of weeks, you can speed up flowering by moving the buds to a warm room. Check the branches frequently; they will need regular misting to prevent buds from drying out. You should also change the water every three days.
Select branches that are least 1 foot long with many enlarged buds and prune branches from all sides of the shrub to maintain symmetry. Whichever shrub you choose, make sure you cut each branch all the way to the main stem. You can always shorten the branches later if they are too long for the vase.
What Plants to Choose?
Pussy willow, flowering quince, and forsythia are among the most common and easiest woody plants cut for forcing. Nanking cherry, corneiliancherry dogwood, vernal witchhazel and clove currant are not as common but are very easy to force and they make excellent landscape plants as well. The spicy clove scent and rich yellow color of the clove currant will brighten any day.
Suitable branches can also be cut from other willows, wild plum, serviceberry, cherries, lilacs, flowering quinces and red maple. It's best to wait until March or perhaps April to take cuttings from harder-to-force ornamentals such as crabapple, magnolia and redbud. Late winter is also a great time to collect the bare branches of hazelnuts, alders, birches and hornbeams to force and elongate their slim, pendulous catkin flowers.
Nebraska Statewide Arboretum is a nonprofit that works toward sustainable home and community landscapes through initiatives in education, public gardens and the environment. Plant and landscape resources at http://arboretum.unl.edu.