Lilacs, crabapples, forsythia and many other shrubs and trees develop flower buds the previous growing season. Before they bloom, they go through dormancy. As the weather warms up the buds leave dormancy and begin to open. Typically, we will see these plants blooming late March or early April.
By bringing cuttings of these plants indoors now through early March, you can force them into an early bloom to enjoy in the classroom. Identify branches with plenty of flower buds. Some branches may have leaf buds which are smaller and more pointed than the rounded, plump flower buds. If you’re not sure what kind of buds you’re observing, cut one bud open and inspect for flower parts. If the plants were pruned in the fall they are not a good option for this project because they will not flower well. On a mild day, cut branches into sections at least 12-inches long. Teach students to harvest safely and respectfully to avoid hurting anyone or damaging the plant.
Bring the branches inside and cut to the desired length. Fill a vase with water. Remove any plant material from the branch that will be under water once inserted into the vase. Keep the vase of cuttings in a warm room away from direct sun. Change the water in the vase daily to prevent bacteria from developing. When the blooms begin to open they can be kept in a cooler location to preserve the flowers as long as possible. Select a variety of spring flowering trees/shrubs to force and students can create an attractive display. Here are some options to consider:
- Forsythia
- Pussy willow
- Witch hazel
- Crabapple
- Magnolia
- Dogwood
- Birch
- Red maple
- Lilac
The length of time it takes for blooms to open varies depending on the type of plant. Forsythia and pussy willow are two quicker options. They take about one to three weeks to force blooming.
Classroom Connections
This activity easily lends itself to a variety of standards. This is not an exhaustive list.
Here are a few examples for science integration.:
- Allow students to plan and carry out the investigation determining what will happen with branches that are cut and placed in water indoors.
- Experiment with varying the conditions and observe the response of the cut stems.
- Evaluate the effects of differing levels of light/water/temperature on flower development. Students can create graphs to show how quickly different plants flower under the same growing conditions.
- Dissect the flowers, once developed, and identify the various parts.
- Research the difference between flower and leaf buds.
- Present research about why plants have flowers (elementary).
- Present research and findings on the effects of varied environments on forcing stems to flower early (high school).
- Write instructions for how to force spring-blooming trees and shrubs to flower.