Garden Variety: Jump-start spring by forcing bulbs, branches
Spring is still months away in northeast Kansas, but spring flowers can be here earlier with a little jump-start indoors. Stems of spring-flowering shrubs and trees such as forsythia, quince and redbud, as well as spring-flowering bulbs such as tulips and paperwhites, can be forced into blooming early indoors.
For shrubs and trees, the forcing process only works with plants that form their buds in the previous growing season. Forsythia, redbud, serviceberry, crabapple, red maple, Japanese maple, pussy willow and lilac are good candidates for forcing blooms. Plants require a chilling period. For most of the species mentioned, that means the plants should be exposed to about eight weeks of temperatures below 40 degrees. This typically occurs by late January or early February in northeast Kansas.
The process is to cut branches from one or more of the ideal plant species. Branches should be 1 to 2 feet long and have many buds. Immediately after cutting, place the cut end of the branch into a bucket with 4 to 5 inches of water in it. A 5-gallon bucket is ideal.
Place the bucket in a cool area, such as a basement or garage (60 degrees is ideal). Check the water every few days and change it if it looks cloudy or scum appears on the top. When buds swell and get ready to open, move branches to a bright room or near a window with indirect light. They can be placed in a large vase with water at this point.
The amount of time it takes for branches to bloom depends on the plant and how close it is to natural bloom time. Willow typically blooms from cuttings very quickly, while lilac branches may take up to four weeks.
Tulips are grown from bulbs that require a chilling period to induce flowering. If you purchased bulbs last fall but were unable to get them planted, forcing is the perfect use for them. Otherwise, you might still be able to find tulip bulbs at some garden centers.
Wrap unplanted bulbs in newspaper or put them in paper bags and place them in the refrigerator. Then, put a reminder in your calendar to remove them in six weeks, or write the date on the package. Avoid storing the bulbs with apples or pears as they release a plant hormone (ethylene) that can cause the bulbs to degrade.
When the chilling period is complete, plant tulip bulbs in a planter with high-quality potting mix. Bulbs can be placed so that they are almost touching with the pointed end up. The bottom of the bulb should be about 6 inches from the top of the planter. Fill the planter with soil to just below the rim and tap the pot lightly to help the soil settle around the bulbs. Then, set the pot in a sink or bathtub and water thoroughly.
Place the pots in a cool basement or unheated garage for a few weeks, and they should begin to sprout. Then, move them to a bright room or near a window.
Paperwhite narcissus bulbs can be forced into bloom without a cold period and should be easy to find in late winter in garden centers. Instead of using soil, plant paperwhite bulbs in a clear planter with glass beads, decorative stones, or something similar. Place the beads or stones in the bottom of the container, set the bulbs in and place enough beads or stones around the bulbs to hold them in place. Add water until it is just below the bottom of the bulb and check it every few days to maintain this level.
When the shoot appears and is 1 to 2 inches tall, pour the water out and replace it with a 4% to 6% alcohol solution. If using rubbing alcohol (which is 70% alcohol), mix it as one part rubbing alcohol to 10 or 11 parts water. You could also use liquor such as vodka or whiskey, but avoid using alcohol that contains sugars or other additives.
The alcohol stunts the growth of the flower stem, keeping it from reaching a height where it would fall over. It does not affect the flower.
Paperwhites usually bloom three to six weeks after planting.
— Jennifer Smith works in regulatory horticulture and has worked as a horticulturist for various government entities. She has experience in landscape design and maintenance and as an educator.