The Paperwhite, a variety of narcissus botanically known as Narcissus tazetta, is admired for its fragrant clusters of white flowers. Unlike many other spring-blooming bulbs, Paperwhites do not require a period of cold dormancy, which makes them uniquely suited for indoor cultivation during winter. The practice of “forcing” involves stimulating these bulbs to flower out of their natural season. This process is simple, often requiring only water and a supporting medium, allowing gardeners to enjoy blooms within four to six weeks.
Selecting Materials and Bulbs
The success of forcing Paperwhites begins with choosing large, firm bulbs. A circumference of 17 centimeters or more indicates a higher stored energy reserve for flowering. While ‘Ziva’ is the most common variety, others like ‘Ariel’ or ‘Grand Soleil d’Or’ offer different bloom times and fragrance profiles.
The forcing container must be watertight and provide three to five inches of depth for root growth. Since Paperwhites are forced without soil, the medium must provide stability for the tall stems. The medium anchors the bulbs while allowing water to circulate freely around the developing roots. Options include:
- Clean pebbles
- Small river stones
- Glass beads
- Gravel
Step-by-Step Guide for Water Forcing
To begin the forcing process, place a layer of your chosen medium at the base of the container, filling it approximately halfway. Arrange the Paperwhite bulbs closely together on top of this layer, with the pointed end facing upward. They should be nearly touching for mutual support during growth. Add more medium around and between the bulbs to secure them, but the top third of each bulb must remain exposed.
Introduce clean water slowly until the level just reaches the base of the bulbs. Ensure the bulb itself is not submerged, as this prevents rot. Move the container to a cool, dark location for approximately one week, maintaining temperatures around 50 to 60 degrees Fahrenheit. This period encourages vigorous root growth before the green shoots emerge. Once the roots are visibly established and the shoots are one to two inches tall, the container is ready to be moved to its final display location.
Maintaining Growth and Controlling Height
Growth Maintenance
Paperwhites often grow too tall in warm indoor conditions, resulting in weak stems that flop under the weight of the flower clusters. After the initial rooting period, move the container to a bright location with indirect light to support healthy, steady growth. Maintaining the ambient temperature between 60 and 65 degrees Fahrenheit helps slow the growth rate and prolongs the bloom period. It is important to check the water level daily, replenishing it to maintain contact only with the base of the roots, never submerging the bulb itself.
Height Control
A specialized technique, often called the “booze trick,” can be employed to limit the height of the stems without compromising flower size. This method utilizes a dilute alcohol solution to suppress cell elongation in the stalk. Once the green shoots are visible and the roots are established, pour off the plain water and replace it with a solution containing 4 to 6 percent ethanol. To achieve this concentration, mix one part of a 40-percent distilled spirit, such as vodka or gin, with seven parts water. This treatment can reduce stem height by up to one-third, resulting in sturdier plants that are less likely to require staking.
Post-Bloom Care
Once the Paperwhite flowers have faded, the bulbs are typically treated as a temporary annual houseplant. When forced in water and pebbles, the bulbs use up nearly all their stored energy reserves to produce the blooms. The absence of soil and nutrients during the forcing process leaves the bulbs severely depleted and unable to replenish the energy required to flower again the following season.
Therefore, attempting to re-force the same bulbs indoors is not recommended, as it rarely yields a robust bloom. The most efficient approach for gardeners in colder climates is to simply discard the spent bulbs and the forcing medium. Gardeners in warmer regions, specifically USDA Hardiness Zones 8 through 10, may attempt to plant the bulbs outdoors, where the foliage can mature and potentially rebuild enough energy for a bloom in subsequent years.