Amaryllis is a bulb and can be kept to bloom again, as long as the bulb is well replenished.
As the glorious blooms wither, cut them off but leave the full stem to die back naturally (once it shrivels, snip it off at the base). The stem, along with the leaves, helps the bulb to build up energy. Give your amaryllis lots of sunlight, food and water—the more vigorous the leafy growth the better.
Once all danger of frost is past, put the plant outdoors in a shady spot, gradually acclimatizing it to more sun (about six hours a day). Sink the pot into the soil and continue feeding and watering. At summer’s end, the leaves will start yellowing as the bulb moves into dormancy. Stop watering and feeding and let the bulb dry out. Bring it indoors before frost. Trim off the dead leaves and store the bulb, in its pot or loose, in a cool, dark location for eight to 10 weeks. Check occasionally for signs of new growth. When those appear, repot the bulb in fresh soil in a container the same size (amaryllis likes being pot-bound). Water thoroughly and set in a warm, sunny spot. Flowers should appear in four to six weeks.
photo courtesy of Dig.Drop.Done