Branches of spring-blooming shrubs such as forsythia can be brought indoors and forced into bloom. (Robin Carlson/ Chicago Botanic Garden photo)
I have a lot of pruning to do in my garden before spring and was wondering if I could force some of the branches into flower.
— Harvey Johnson, Winnetka
A number of trees and shrubs that flower in spring can be forced into bloom indoors in late winter. A vase of blooming forsythia or lilac branches can brighten a room.
It may take one to eight weeks for the blossoms to open. The closer to their natural bloom time that you cut the branches, the sooner they will open.
The branches should be at least 1 foot long, full of fat flower buds, and cut on a day when the temperature is above freezing. Cut a few more branches than you expect to need, because some may fail to bloom. Use a sharp pair of pruners and take care not to disfigure the shrub or tree while harvesting branches.
Remove any buds and twigs that will be underwater in a vase. Place the cut branches in a container of warm water and, while holding the end of the branch underwater, make a new cut 1 inch from the base of each stem. Trimming the stems underwater will help prevent air that might block water uptake from entering the stem through the cut end.
Keep the branches standing in water in a cool room out of direct sunlight and change the water every other day. You also can add a floral preservative to the container water to help control bacteria and reduce the need to change the water.
Good choices for forcing in March include serviceberry (Amelanchier), magnolia, flowering quince (Chaenomeles), forsythia, crab apple or apple (Malus), flowering pear (Pyrus), flowering cherry (Prunus), pussy willow (Salix), spring-flowering witch hazel (Hamamelis vernalis), lilac (Syringa) and redbud (Cercis).
Tim Johnson is director of horticulture for the Chicago Botanic Garden in Glencoe (chicagobotanic.org). Send questions to: Gardening Q&A, Sunday, Chicago Tribune, 435 N. Michigan Ave., Chicago, IL 60611-4041; e-mail to firstname.lastname@example.org.