UVM Ext: Forcing branches for winter flowers Weekend Magazine

Forsythia in February? Impossible, you say? Not so. A vase full of flowers from the garden requires no more effort than collecting a few branches to force them to flower.

The right time to pick cuttings for shoots is when the annual winter pruning is done. If pruning isn’t one of your winter things to do, just look around your yard. What trees and shrubs bloom in the spring? They lay out their buds in the previous growing season, so they are ready to bloom when spring arrives (or fools them into making it happen).

To force early winter, choose varieties that bloom in early spring. Shrubs such as witch hazel (Hamamelis) and forsythia (Forsythia) are good choices. In the middle of winter you can try the flowering quince (Chaenomeles), azalea and rhododendron (Rhododendron), crayfish and apples (Malus) or cherries (Prunus). In late winter, the lilac (Syringa), spirea (Spiraea) and mock orange (Philadelphus) can be forced to bloom indoors.

Generally, varieties that bloom earlier in the spring can be cut earlier and forced in the winter than those that bloom later in the spring. Each can be cut and flowered until the time of outdoor flowering. Imagine a vase full of lilacs and forsythia while there is still snow on the ground outside the window.

Since these plants are programmed to bloom with the advent of winter, they need a cold time. If you have experienced temperatures below 40 degrees Fahrenheit for at least six to eight weeks, you can start harvesting the branches for shoots. Take a pruner and go outside. The best time to cut is when the temperature is mild.

Always use good pruning practices. Keep in mind that what you cut now will affect the spring flowering of your tree or shrub, as well as its future growth and shape. To learn more about pruning, you can find useful information at go.uvm.edu/pruning-dormant-plants online.

Cut segments at least one or two feet long, longer if you want a truly dramatic display. More flower buds means more flowers. Although it can be difficult to distinguish between flower buds and leaf buds, flower buds are generally fatter and leaf buds are sharper.

If you have collected enough cuttings, bring them in. Fill a container with warm water. Cut off the end of each branch at a sharp angle and cut through the end vertically or crush it slightly to allow more water to enter.

Remove any side branches or twigs that will be under water. Then arrange the cuttings in the container.

Place the container in indirect light, such as in a north-facing window, away from drafts and heat sources. Be sure to change the water often, at least every few days, to keep it fresh.

The buds can fall off if the indoor environment is very dry, so daily humidification or covering the branches and container with a large, transparent plastic bag can increase the required humidity until the buds open.

If the buds fall off, you may have picked your cuttings too soon. Don’t hesitate to try again. The later in winter and closer to the flowering time of nature, the greater the chance of successful coercion.

Above all, be patient. The process can take up to a month, sometimes longer. But as you watch, you will witness an early spring as the buds swell. And you will be rewarded with a vase full of flowers while there is still snow on the ground outside the window.

Sometimes it is very good to deceive mother nature.

Deborah J. Benoit is a UVM Extension master mardener from North Adams, Massachusetts, who is a member of the Bennington County Department in Vermont.


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