Although the flower stalks should be cut off near the top of the bulb after blossoms die, long strap-like leaves must remain intact. A location with as much sunlight as possible is required to help the bulb bulk up for flowering the next winter. It will also need water and fertilizer.
When the threat of frost is gone, amaryllis plants are safe outdoors. The plants need water daily and fertilizer every two weeks. Although some of the leaves are likely to wither, bulb growth will continue. On rare occasions, an amaryllis may bloom again during this time. To encourage flowering at the holidays it must enter dormancy---during which the leaves wither---in mid-August.
Dormancy requires that you stop watering the plant and place it in an outdoor location where temperatures average 55 degrees Fahrenheit. If it's too hot to do this, wait until autumn. Then bring the withered plant indoors before frost. Take the bulb out of the pot, remove the dirt and store it in a cool location to be repotted in eight to 10 weeks.