This article was published originally on 1/7/2009
Amaryllis bulbs are forced indoors for their large, spectacular flowers. Some individuals discard the amaryllis after flowering. However, it is possible to save the amaryllis and force it to flower on an annual basis. The key to successful reflowering is proper care.
After the flowers fade, cut off the flower stalk with a sharp knife. Make the cut 1 to 2 inches above the bulb. Don't damage the foliage. In order for the bulb to bloom again next season, the plant must replenish its depleted food reserves. The strap-like leaves manufacture food for the plant. Place the plant in a sunny window and water when the soil surface is nearly dry. Fertilize every 2 to 4 weeks with a water-soluble houseplant fertilizer.
The amaryllis can be moved outdoors in late May or early June. Harden or acclimate the plant to the outdoors by initially placing it in a shady, protected area. After 2 or 3 days, gradually expose the amaryllis to longer periods of direct sun. Once hardened, select a site in partial to full sun. Dig a hole and set the pot into the ground. Outdoors, continue to water the plant during dry weather. Also, continue to fertilize the amaryllis once or twice a month through July. Bring the plant indoors in mid-September. Plants left indoors should be kept in a sunny window.
In order to bloom, amaryllis bulbs must be exposed to temperatures of 50 to 55 degree F for a minimum of 8 to 10 weeks. This can be accomplished by inducing the plant to go dormant and then storing the dormant bulb at a temperature of 50 to 55 degree F. To induce dormancy, place the plant in cool, semi-dark location in late September and withhold water. Cut off the foliage when the leaves turn brown. Then place the dormant bulb in a 50 to 55 degree F location for at least 8 to 10 weeks. After the cool requirement has been met, start the growth cycle again by watering the bulb and placing it in a well-lighted, 70 to 75 degree F location. Keep the potting soil moist, but not wet, until growth appears. The other option is to place the plant in a well-lighted, 50 to 55 degree F location in fall. Maintain the amaryllis as a green plant from fall to early to mid-winter. After the cool requirement has been met, move the plant to a warmer (70 to 75 degree F) location.
Amaryllis Flower. Photo by Cindy Haynes, ISU Department of Horticulture
IC-500( 1) -- January 7, 2009