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Get Growing: Forcing bulbs for indoor color

  • Narcissus bulbs offer color and fragrance. To keep them from flopping over, you can “pickle” them, a trick developed by a horticulture professor at Cornell named William B. Miller. Getty Images/iStockphoto

  • Beautiful spring narcissus flowers in pot on black background Getty Images/iStockphoto



For the Gazette
Friday, November 30, 2018

This dreary gray weather we’ve been having is a stern reminder of what lies ahead in the next four months. I don’t know about you, but I don’t like the grayness. (I don’t enjoy the cold, either, but I won’t complain about that here.) It saps my energy and drags down my mood. Fortunately, it’s not too late to mount a defense against the winter doldrums by forcing flower bulbs for indoor cheer.

Some bulbs are easier to force than others. The easiest are those that do not need pre-chilling. (Technically, you aren’t “forcing” these bulbs, because “forcing” means that you are tricking the bulbs into blooming earlier by chilling them in a dark place for 12 weeks or more.) These include amaryllis and a group of narcissus known as paperwhites. Because these don’t require months of advance planning, they are my annual go-to favorites.

Amaryllis comes in a rich variety of colors and sizes, stripes and solids, and double and single blooms. You can find amaryllis bulbs at local garden centers as well as supermarkets, big box stores, and even hardware stores. All you need is good quality potting soil and a pot that’s about one inch in diameter bigger than the diameter of the bulb. You can use a simple clay pot or something fancier, as long as it has a drainage hole in the bottom. If you can’t plant the bulb right away, store it in a cool dark place, between 40 and 50 degrees.

When you’re ready to plant, start by soaking the bulb’s base and roots for a few hours in lukewarm water. Then, fill the pot half way with soil, place the bulb in the pot and fill with more soil, leaving the “shoulders” of the bulb exposed. It’s best to leave the top inch or so of the pot empty so that soil doesn’t spill out when you water it. Water lightly and place the pot in a sunny, warm spot. 68 to 70 degrees is ideal.

Amaryllis bulbs appreciate some extra warmth to coax them out of hibernation. They’ll emerge eventually, even without added heat, but I start them on a heating pad on the low setting until they produce a green shoot. Water sparingly until the leaves begin to grow and gradually increase watering. But don’t overdo it. Bloom time varies, but expect it to take 7 to 10 weeks. If you want a continuous festival of blooms, plant a series of bulbs at 2-week intervals.

While you’re waiting for your amaryllis to flower, plant paperwhite bulbs. These come in several varieties. ‘Chinese Sacred Lily’ has white petals with a yellow cup and a mild, citrusy scent. ‘Inbal,’ ‘Galilee’ and ‘Ziva’ have pure white flowers; ‘Ziva’ has a stronger, muskier scent. ‘Grand Soleil d’Or’ has yellow petals with an orange cup, a sweet, fruity scent.

You can plant these in potting soil, leaving the tops of the bulbs exposed. Water lightly. Or you can place them in a bed of pebbles, sea glass, or glass pebbles. Add water to reach the base of the bulbs. Don’t soak the bulbs in water or they will rot. Keep the bulbs in indirect light until they begin to flower, usually 3 to 5 weeks. They can then be moved into direct sunlight, but the cooler they stay, the longer their blooms will last.

Paperwhites tend to flop over when they get tall. You can stake them to prevent this, or you can “pickle” them, a trick developed by a horticulture professor at Cornell named William B. Miller. Miller has determined that a small amount of alcohol added to the paperwhites’ water stunts their growth so their stalks are shorter and sturdier. Any kind of hard alcohol such as whiskey, gin or vodka will do, but the high sugar content of wine and beer make them unsuitable for this purpose. When the bulbs have sprouted, tip out the water and replace it with a mixture that’s around 5% alcohol. For a beverage that’s 40% alcohol, that means adding one part alcohol to 7 parts water. If you don’t have alcoholic beverages on hand (or you don’t want to waste them on your paperwhites), you can use rubbing alcohol. But remember that it’s usually 70% alcohol, so dilute it with 10 parts water.

Pickling your bulbs will reduce the plants’ height by ½ to ⅓. The science behind this isn’t entirely clear, but the theory is that the alcohol reduces the roots’ water absorption. But go easy. A higher concentration of alcohol can kill the plants.

Once paperwhites have finished putting on their show, they can be composted. If you are so inclined, you can overwinter amaryllis in hopes of new bloom next year. Remove the dead flowers, then water and fertilize the plant so that its leaves can photosynthesize, creating nourishment for next year. After the leaves turn brown and wither, the bulb should be kept in a cool, dark place such as an unheated garage, until warm weather returns and they can be placed out of doors. (Some people I know just plant the bulbs in late spring in a sunny place in their gardens and keep them watered.) Bring the bulb back inside in September for a couple of months of dormancy in a cool, dark place. Then the bulbs are ready to coax into bloom again. I confess I have had limited success with this, but I have not always been assiduous in my aftercare regimen.  

Potted bulbs make great holiday gifts for people who don’t want, much less need, more stuff in their lives. Just some colorful cheer to lift their spirits when winter seems interminable.

Mickey Rathbun, an Amherst-based lawyer turned journalist, has written the Get Growing column since 2016.

 Upcoming Garden EventsSee Tower Hill Gardens in a new light

Celebrate the season with thousands of lights, new experiences and enchanting landscapes at Tower Hill Botanic Garden in Boylston. This annual festival of lights is an inclusive, secular event where people of all backgrounds can celebrate winter, light and nature together. This year’s displays explore patterns in nature. Tower Hill offers daytime and nighttime sessions, Day Lights and Night Lights, Nov. 23 to Dec. 30.

During Day Lights, visitors can explore the outdoor gardens and hike through the grounds. Inside, they can tour the decorated rooms and conservatories, enjoy local fresh food at the Café and do holiday shopping at the Garden Shop.

Families with children will enjoy the scavenger hunts, the model train, discovery backpacks, hands-on library activities and more. Adult educational trips, programs and workshops are available for an additional fee. Day Lights is open Wed. through Sun., 11 a.m. to 3 p.m. Entry is included in general admission. Free for members. There will be concerts Dec. 1, 8 and 15.

Night Lights invites visitors to wander through 15 acres of dramatically lit formal gardens and surrounding woodlands, including a walk through the firefly forest that ends at the Wild Rumpus, an amazing stick-work installation by internationally acclaimed artist Patrick Dougherty. Dougherty bends, weaves and flexes locally sourced saplings into architectural sculptures that are unique to the setting and dynamically relate to the landscape and built environment around them. His work is magical. Inside, visitors can enjoy decorated rooms and conservatories, and investigate the model train village.

Night Lights is open Tues. to Thurs., 4 to 9 p.m., and Fri. to Sun., 4 to 10 p.m. It requires non-refundable, pre-purchased tickets for members and non-members.

This is a great time to become a Tower Hill member, helping to sustain the public garden year-round. Members can enter Day Lights for no additional fee and receive 50% off Night Lights ticket prices.

Please note: dogs are not permitted November 24 – December 30, 2018.

For more information, including ticket prices, go to: towerhillbg.org.