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 to bloom during winter is not difficult, and the results are beautiful.
Amaryllis bulbs purchased now should be planted into pots using a good-draining 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 because an amaryllis in bloom can be somewhat top-heavy, clay pots provide a little more stability. You also can buy them pre-planted in pots 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 day so it will grow straight. Otherwise, the stalk will grow towards 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 bulb planting this time of year. Some large bulbs may produce two flower stalks.
Sometime after the flower spike has emerged, leaves will grow from the top of the bulb. After the flowers have faded, cut the stalk at the point where it emerges from the bulb, but do not cut any foliage. Keep the plant inside and continue to provide plenty of sun, or the leaves will be weak. Water it regularly when the soil begins to feel dry, but it is not really necessary to fertilize your amaryllis during this time.
In April, you may plant your bulbs into the garden where they will make a long-lived plant that blooms in spring. Amaryllis planted in the garden this coming spring will get into their natural cycle and bloom in April the following years.
Amaryllis plants thrive in any reasonably good garden soil as long as drainage is good. A spot that receives part sun (about four to six hours of direct sun and then shade in the afternoon) is the ideal location, but I have seen amaryllis thrive in full sun to part shade. Once planted and established, amaryllis can be left alone for several years. A light sprinkling of general-purpose fertilizer in April and watering during unusually dry weather are all they need. Beds should be mulched with and inch or two of pine straw, leaves or other similar material to help reduce weeds and conserve moisture. Increase the thickness of the mulch to 3 or 4 inches during winter to help protect the bulbs from freeze damage.
Paperwhite narcissus bulbs can be purchased now and planted in pots to grow for winter bloom. Planted now, the bulbs should bloom for late December or early January.
Fill a pot with drainage holes about two-thirds full of potting soil. Place the bulbs on the soil with their pointed ends up. Plant enough bulbs in the pot to fill it without the bulbs touching each other. Add enough potting soil to cover the bulbs until the points are just sticking above the soil surface. Water thoroughly.
Place the pots in a shady spot outside if the weather is staying above freezing or 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 place the pot in a very sunny window in an unheated room inside.
When grown too warm or with too little light, paperwhite leaves and flower stalks will be tall and tend flop over. This frequently occurs when people try to force paperwhites in a warm room indoors on a windowsill.
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. 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 variation of this is to grow the bulbs in a bulb vase. Place a single bulb in the vase and add enough water to touch the bottom of the bulb. Maintain the water at this level and follow the directions given above.
Dan Gill is a horticulturist with the LSU AgCenter. He can be reached at DGill@agcenter.lsu.edu.