As we continue to slog through winter, many gardeners start getting desperate for signs of spring. Fortunately, we can cheer up the mid-winter doldrums by forcing branches.
“Forcing” means to manipulate plants into growing or blooming before their normal season. Trees and shrubs that flower in spring —like forsythia, maple, and witch hazel—formed their buds last fall. They’re primed to bloom as soon as they warm up. So by cutting stems and putting them in water, we can coax them into flowering several weeks before they would outside.
Plants for Forcing in Winter
Our favorite plants for winter forcing are trees and shrubs that normally bloom in early spring, from late February to about mid-April. These plants need a dormant period of about eight weeks of temperatures below 40°F before they’re ready to force, which means you can start cutting these plants as early as late January. The closer they are to their normal bloom time when you cut them, the less time they’ll take to bloom in a vase.
These early spring-flowering shrubs have small blooms and take as little as two weeks to flower in a vase:
- Bridal wreath spirea (Spirea prunifolia)
- Forsythia (Forsythia spp.)
- Spicebush (Lindera benzoin. Native to Indiana.)
- Red-twig dogwood (Cornus sericea. Native to Indiana,)
- Witch hazel (Hamamelis vernalis or the hybrids. Indiana’s native H. virginiana blooms in fall.)
- Pussy willow (Salix discolor. Native to Indiana.)
Generally speaking, tree branches take a little longer to force than shrubs do. Choose slender, young branches, not thick limbs. Fruit trees require yearly pruning, so we prune apples and pears every year in February and bring some of the prunings in to force.
- Apples and crabapples (Malus spp.)
- Beech (Fagus spp. Fagus grandiflora is native to Indiana.)
- Birch (Betula spp. Several are native to Indiana. )
- Pears (Pyrus spp.)
- Red maple (Acer rubrum. Native to Indiana.)
- Serviceberry (Amelanchier spp. Several are native to Indiana.)
- Weeping willow (Salix babylonica)
While we particularly like the early spring bloomers, you can also force many plants that bloom from mid-April into May. Don’t start cutting these before March, or you’ll delay their bloom by several weeks.
- Cherry (Prunus spp., ornamental or fruiting)
- Lilac (Syringa spp.)
- Magnolia (Magnolia spp.)
- Redbud (Cercis canadensis. Native to Indiana.)
- Rhododendron (Rhododendron spp.)
- Wisteria (Wisteria spp.)
If you start a new branch or two every two weeks, you can have indoor blooms from February to April! Check out this publication from Purdue Cooperative Extension Service for even more plants for forcing.
How to Force Branches
- Collect your branches for forcing on a mild day.
- Pick a day with temperatures in the high twenties or warmer.
- Choose young, slender branches or stems with lots of buds.
- Younger branches are more flexible and have buds that break dormancy easily.
- Cut your branches about 6″ to 18″ using a sharp pair of pruners.
- For trees, carefully prune small branches or twigs at the branch collar: the point where a branch meets a limb.
- For shrubs, cut at the branch collar or cut a slender stem off at the ground.
- Bring the branches inside and submerge them in tepid water to condition them.
- Fill a tub with lukewarm water and lay the branches in it, completely submerging them. This soak helps loosen up the bud scales.
- If you’ve cut when the temperatures are above freezing, soak for a couple of hours.
- If you’ve cut when the temperatures are below freezing, soak from four hours to overnight. Otherwise the buds might burst too quickly.
- After conditioning the branches, fill your container with lukewarm water.
- Some people add floral preservative to the water, but it’s not strictly necessary.
- Make a fresh, angled cut at the desired length and immediately put cut branches into the container.
That’s it! Change the water weekly, or if it starts to look cloudy. Forced branches do best in a relatively cool spot and out of bright sunlight.
Bonus! Making New Plants from Forced Stems
Some stems will develop roots in water, and you can use them to propagate new plants! This process is called rooting in water. It works better with stem cuttings from shrubs than branch cuttings from trees.
If you want to give it a try, we recommend forcing your stems in clear vases so you can watch roots develop.
- Follow the instructions for forcing.
- When the roots are about 1/4″ to 3/8″ long, take the forced stem out of the water .
- Cut the top off to make the stem 6″ to 8″ long. You now have a cutting.
- Stick the cutting into a pot filled with moist potting soil, covering the baby roots.
- Keep the soil moist until the cutting develops permanent roots.
- When the soil outside dries out enough for planting, transplant the cutting into a garden bed.
Enjoy Your Garden in Winter
Forcing branches is just one way to make the most of the garden in winter! Find others with Feeding Birds in the Winter Garden, Design for the Garden in Winter, and our other posts about the colder months outdoors.
We can help you create an outdoor space that offers you beauty in winter and all year round. Contact us today to discuss your four-season garden!