“Groundwork” column for Oct. 28, 2012
Paperwhite and amaryllis are two bulbs that are popular for forcing in Louisiana during the winter. Forcing bulbs means growing them to bloom earlier than they would under normal landscape conditions. Paperwhite bulbs and amaryllis bulbs are commonly available from November to late December. Forcing them for bloom during the winter is not difficult and the results are beautiful.
Amaryllis bulbs purchased now should be planted into pots using a well-drained potting soil with the neck of the bulb above the soil surface. The pot should be large enough so that there is about 1 inch of clearance between the pot rim and the bulb. 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. You can also buy them preplanted in pots and ready to grow.
Place the pot in a sunny window (the more sun the better), and keep the soil evenly moist. When the flower stalk begins to emerge, rotate the pot about one-half turn every few days so it will grow straight. Otherwise, it will grow toward the window and look awkward. If you provide your amaryllis with too little light, the flower stalk will grow excessively tall and may even fall over. Flowering generally occurs in about six or seven weeks from bulbs planted this time of year. Some large bulbs will produce two flower stalks.
Paperwhite narcissus bulbs can be purchased now and planted in pots to grow for winter bloom. Fill a pot with drainage holes about two-thirds full of potting soil. Place the bulbs with their pointed ends up on the soil. Plant enough bulbs in the pot to fill it without the bulbs touching each other. Add enough potting soil to cover the bulbs with the points just sticking above the soil surface. Water thoroughly.
Place the pots in a shady spot outside if the weather is staying above freezing; otherwise, put them in an unheated garage. Water enough to keep the soil moist. When you see the tips of the leaves showing, move the pot to a sunny location outside if temperatures are staying above freezing or in a sunny window in an unheated room inside.
Grown in too warm a temperature or with too little light, the leaves and flower stalks will be tall and tend to flop over. This frequently occurs when people try to force paperwhites on a windowsill in a warm room indoors.
Placing the pots in a sunny spot outside generally produces the best results. Just bring the pot inside on those nights when freezing temperatures are predicted and place it back outside when the freeze is over.
When the first flower buds open, move the pot indoors to enjoy them. If possible, move the pot of paperwhites into a cool, unheated location at night and back to its display location during the day. This will make the flowers last longer.
Paperwhites may also be grown in bowls of pebbles and water. Choose a shallow, decorative bowl and fill it half full of river stones, pebbles or marble chips. 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 in a cool, sunny area.
A trick to maintain sturdy and shorter leaves and flower stalks is to add alcohol to the water when forcing paperwhite bulbs. The alcohol interferes with water uptake and results in an overall smaller plant. Typically, paperwhites grown indoors produce tall, floppy leaves. Using alcohol will result in stems a third shorter than normal making for a much nicer plant.
Start the bulbs off in water. When roots have formed and the emerging foliage is 1 to 2 inches long, empty the water and replace with a solution of 4 to 6 percent alcohol. If you are using 80 proof liquor (40 percent alcohol), that works out to one part gin (or similar) to 7 parts water.
Rubbing alcohol (70 percent isopropyl alcohol) can be substituted. Dilute it mixing 13 parts water to 1 part rubbing alcohol.
Got a gardening question? Write to Bob Souvestre, horticulturist with the LSU AgCenter, at Burden Center, 4560 Essen Lane, Baton Rouge, LA 70809, or email to bsouvestre@agcenter.lsu.edu, or call Master Gardeners at (225) 763-3990.