When grown as a houseplant, amaryllis is a bright favorite known for its tender bulbs. The amaryllis boasts two to four or more flowers attached to a 12 to 24 inch stalk or scape, and flowers reaching up to ten inches across. The amaryllis has a brilliant color range: brilliant red, orange, salmon pink, white, striped, or variegated. Also attractive are the few pest problems encountered by the amaryllis, although mealybugs sometimes infest bulbs and leaf bases. Amaryllis grown as houseplants belong to the genus Hippeastrum are hybrids between many species of Hippeastrum native to tropical South America and Amaryllis belladonna, a closely related plant native to South Africa. Bulbs can be bought as early as SEPTEMBER, from garden centers florists and mail order firms. Bulbs 3 inches or more in diameter provide the largest flowers.
Amaryllis is best grown in a porous growing medium which allows air to reach the roots. The container used must have drainage holes and should be at least 5 inches deep and 2 inches larger in diameter than the bulb. Clay or ceramic containers are recommended.
When planting an amaryllis bulb, there are several things to keep in mind. When planted, the final level of the medium should be about one inch below the top of the pot. After planting, water thoroughly. Although it is best to use rain water, tap water may also be used to water the bulb. If using tap water, allow it to sit for a day to let the chlorine evaporate. The potted bulb should be kept warm (70F), but does not have to be placed in a sunny window until sufficient root growth has developed. The plant should be watered carefully for the next five weeks; the bulb does not require much moisture at first. It should be watered thoroughly, from above or below, and growing medium should dry out somewhat before watering again. To determine if watering is necessary, it is possible to check for moisture in the growing medium about 1/2 inch below the surface, or to lift the pot to feel the weight. If the bulb was packaged in a pot without drainage holes, care must be taken not to overwater, as overwatered bulbs tend to shrivel up. To determine overwatering, squeeze the bulb occasionally to find out if it is firm. Or, you may check by tipping the pot. In these cases, drainage holes should be added or the bulb transferred to a pot with drainage holes.
When either the leaves or the flower stalk appear, the pot should be moved to a sunny window. The pot should be turned a bit each day to keep the flower stalk growing straight. During stalk elongation, the plant should be watered frequently; amaryllis use much water at this stage. Also, at this stage the stalk may need to be staked. To enhance bloom quality, a houseplant fertilizer should be applied weekly. Flowers may last longer if the anthers are removed before they start shedding pollen. Also, to prolong the flower life, place the pot in a slightly cooler area.
After flowering, when the flower stalk has completely dried out, the floral stalk should be cut 2 to 3 inches above the bulb. If planning on saving seeds, take care not to damage the strap-like leaves. The leaves will keep growing and may grow up to 3 feet in length and 4 inches wide. Watering should be continued, but only as the growing medium dries out, as the bulb is susceptible to rot at this stage. The plant should still be regularly fertilized, using a complete house plant fertilizer high in phosphorous such as 5-10-5 or 15-30-15 or using bone meal, following manufacturer's recommendations. The foliage should be kept growing vigorously, because it produces the food for the next year's bloom. There are two ways to handle the bulb at this time: To keep it growing and allow it to flower naturally or to schedule it to flower at a specific time.
When scheduling bulb flowering, it is advisable to wait five to six months after flowering has ended and then stop fertilizing. Reduce watering gradually over a 3-week period, then completely stop watering; the plant will have finished its growing cycle and begun its resting period. For 2 to 3 months, the pot should be kept in a cool (50 to 60 F), dry, well-ventilated place for 2 to 3 months. Lay the pot on its side to ensure that no water moistens the bulb. In November or later, the potted plant should be moved into a warm, bright area to being the growth cycle again. The bulb should flower within 4 to 8 weeks from the time watering is started.
Bulb should be repotted every three or four years, because the roots are sensitive and should not be disturbed often. Delicate repotting should be done just before the bulb's dormancy is broken. When repotting, the bulb should be taken out of its old container and as much growing medium as possible removed from the roots by pouring water over them. The bulb and mass of roots should be placed in the center of a pot 2 inches larger in the diameter than the bulb, the empty space filled carefully with a good porous growing medium, taking care not to damage the roots. After the medium has been firmed around the roots, the base of the pot should be immersed in a bucket of water for about a half hour to make certain the medium is thoroughly moistened.
When propagating from offsets, upon lifting the bulb for repotting, just before breaking dormancy, small offsets known as BULBILS can be found clustered around the base of the mother bulb and should be detached with fingers or sharp knife. The bulbils can be grown in a plastic tray or large pot with a porous growing medium. After 12 months, the bulbils will be big enough to plant in individual small pots and can be grown for one year and then moved to another pot about twice their size. The bulbs will bloom in three or four years after being removed.