Amaryllis (Hippeastrum species) originates from the tropical regions of South America and is easy to grow, producing big, beautiful flowers in dazzling shades of red, pink, white or orange. Their ability to bloom in winter makes them a popular indoor plant for an added splash of decorative color.
Bulb Selection and Preparation
According to Carl Hoffman and Mary Meyer of the University of Minnesota Extension, performance of an amaryllis plant is dependent upon the size and condition of the bulb. The larger the bulb, the more flowers it is capable of producing. Look for bulbs that are free of mold and decay. Also be watchful for any signs of injury. If not planted right away, amaryllis bulbs should be stored at a cool temperature not to exceed 50 degrees F. Prior to planting, the bulbs should be soaked for two to three hours in lukewarm water.
Amaryllis bulbs thrive in composted soil that is full of nutrients and able to drain well. They also prefer a small environment, so the potting container should only be 1 inch in diameter larger than the bulb. Position the bulb in the potting soil so that one-third to one-half of it is exposed above the soil. Pack the soil firmly around the bulb and water thoroughly. Fertilizer should not be used until growth is present. Place the container in a warm spot that has an adequate, direct light source. The heat will develop the stems.
Growth and Care
Lightly water the amaryllis bulbs until the stems begin to appear. Increase watering as foliage emerges. Now is the time to introduce a high phosphorous fertilizer to feed the plant. Fertilizer contains a mixture of the three major nutrients plants need: nitrogen, phosphorous and potassium (NPK). Each nutrient is a percentage of the entire mixture. For example, a 10-10-10 fertilizer contains 10 percent each of nitrogen, phosphorous and potassium. In a high phosphorous fertilizer, the second percentage number will be higher than the others, such as a 5-10-5 or 11-35-15. High phosphorous content aids in flowering and bloom size.
Amaryllis are heavy feeders, so fertilize every two to three weeks. Once the buds begin to show some color, move the plant out of direct light to prolong the bloom color. The plants can take seven to 10 weeks to flower, with winter flowerings taking longer to appear than in the spring.
Amaryllis will grow year after year if proper care is taken to maintain the plants after the flowers have faded. Remove the faded blooms to prevent seed formation, and only remove the flower stalks and leaves after they have died back and appear yellow. The stalks help produce nutrients that are stored in the bulb to aid the next season’s growth. Store the spent bulbs in a cool spot such as a basement or closet to give them a rest period. Do not water the plant, and remove the rest of the dry, yellowed foliage. After eight to 12 weeks, move the amaryllis bulbs back to their light source to begin the growth cycle again. This is also a good time to repot the bulbs to rejuvenate the soil.
Pests and Disease
Few pests and diseases will attack amaryllis plants in the house. They are more prevalent on those plants grown under greenhouse conditions. The narcissus bulb fly (Merodon spp.) lays its eggs inside amaryllis bulbs that have been moved outside for the summer season. Wilted, distorted foliage is the first sign of infestation, and the use of insecticides on these pests is not effective. Infected bulbs should be destroyed. Red blotch (Stagonospora curtissi) is a fungus that develops into cankers on the stalk base and on emerging leaves. The plant foliage may become distorted and unsightly, but red blotch is rarely fatal. If the fungus is persistent, treat the bulbs with a systemic fungicide.