Forcing is a horticultural term that means manipulating a plant’s environment, primarily the light and temperature, to get it to bloom at the desired time.

Although you may not realize it, you are already familiar with many examples. For instance, the date Easter occurs varies widely from year to year, yet Easter lily growers are always able to produce blooming Easter lilies at exactly the right time.

Northern gardeners force spring-flowering bulbs, like tulips, daffodils and hyacinths, to bloom early in pots. But this is not commonly done here in the South.

I would, however, recommend you try forcing two types of bulbs, paperwhites and amaryllises. These bulbs do not require a chilling period prior to forcing, are easy to grow and can provide beautiful flowers during the winter holidays.

How to force paperwhites to bloom early with distilled spirits (copy)

Paperwhites need a sunny spot indoors or outside.

Forcing paperwhites

Paperwhite bulbs can be purchased and planted in pots November through January. They generally bloom in about three weeks, so we are not forcing them to bloom much earlier than they would in our gardens. Paperwhites typically bloom in January and February here.

Fill a pot about two-thirds with potting soil, then place the bulbs on the surface. Put enough bulbs to fill the pot without the bulbs touching each other. Finish filling the pot with potting soil so that you still see the tips of the bulbs exposed.

Paperwhites may also be grown in bowls of pebbles and water. Choose a decorative bowl or container without drainage holes and place a layer of gravel, pebbles or marble chips on the bottom. Place the bulbs on the surface and add enough rocks so that the bulbs are two-thirds covered. Add enough water to touch the bottom of the bulbs and maintain the water at this level.

Place the container of bulbs in a sunny, cool location. A sunny window in a cool room can work, but placing the pot in a sunny spot outside generally produces the best results. Bring it inside on those nights when freezing temperatures are predicted. When the first flower buds open, bring the pot indoors to enjoy (Note: Some people find the fragrance of paperwhites unpleasant).

After the flowers fade, you can plant the growing bulbs outside in a bed that receives full to part sun, where they will bloom year after year.

Keeping height in check

A common problem when forcing paperwhites indoors is that they grow too tall, and the leaves and flower stalks tend to be floppy. This happens because it is too warm and there too little light. This can be prevented by growing the bulbs outdoors as described above.

There is, however, another technique to prevent floppy paperwhites. I was once asked about using alcohol to make paperwhites bloom shorter. I must admit, I’ve heard lots of off-the-wall gardening recommendations over the years, and my initial reaction was quite skeptical. But I found research done at Cornell University that shows this to be true. Here’s how to do it.

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Amaryllis bulbs make great hostess gifts. Place the pot indoors in a sunny window (the more sun the better) and keep the soil evenly moist. Once the flower stalk emerges, turn the pot every few days so it will grow straight and not bend toward the window.  

Plant the bulbs in containers of pebbles with water as described above. Wait about one week until roots are growing, and the green shoot is growing about 1 to 2 inches above the top of the bulb. At this point, pour off the water and replace it with a solution of 4% to 6% alcohol, made from just about any hard liquor. To get a 5% solution from a 40% distilled spirit (gin, vodka, whiskey, rum, tequila — but do not use beer or wine), you add one part of the booze to seven parts of water. If plants are given more than 10% alcohol, growth problems will start, and 25% alcohol is dramatically toxic. So, moderation is the key.

Then, simply use this solution whenever you need to add water to maintain the proper level. The result will be a plant that is one-third shorter, but with flowers just as large, fragrant and long-lasting as usual. The plant will be nicely proportioned and won’t need support stakes to keep it upright.

Forcing amaryllis

To have blooming amaryllis bulbs now, we are forcing them to bloom much earlier than they do in our gardens. When amaryllis bulbs are dug and dried out for shipping, it triggers them to produce flowers during winter rather than in April, which is their normal time to bloom.

You may purchase pre-potted amaryllis bulbs ready to grow or choose loose bulbs and pot them up yourself. The pot should be large enough to have about a 1-inch clearance between the pot rim and the bulb. Plant the bulb so that the upper one-fourth is exposed. Clay or plastic pots may be used, but since an amaryllis in bloom can be somewhat top-heavy, clay pots provide a little more stability.

Place the pot indoors in a sunny window (the more sun the better) and keep the soil evenly moist. Once the flower stalk emerges, turn the pot every few days so it will grow straight and not bend toward the window. If you provide your amaryllis with too little light, the flower stalk may grow excessively tall and may even fall over. Some large bulbs will produce two flower stalks.

After the flowers have faded, cut the stalk at the point where it emerges from the bulb. Do not cut any foliage. Keep the plant inside and continue to provide plenty of light or the leaves will be floppy. Water it regularly when the soil begins to feel dry, but it is not necessary to fertilize your amaryllis during this time.

When April arrives, it’s time to plant your bulbs into the garden. Amaryllis planted in the garden this coming spring will get into their natural cycle and bloom in April the following years.

The German tradition of decorating a cut evergreen tree is a popular way to celebrate the Christmas season.

Garden columnist Dan Gill answers readers’ questions each week. To send a question, email Gill at [email protected] 

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