Amaryllises are usually household potted plants, but can be grown in the outdoor garden in USDA hardiness zones 3 to 9, if desired. Amaryllises do not require a dormant period in order to survive, but in outdoor gardens in most zones, it is inevitable. In addition, to ensure new blooms each year, it is best to also prepare the indoor potted bulbs for and simulate winter dormancy so they will surely bloom again in the spring.
Stop watering and fertilizing your amaryllis plants in October. Potted amaryllises do not need water or food after this point and by withholding them, the bulbs will begin to get ready for the dormant season. It's OK for rain to water on your garden amaryllises. You can't control that. Cooler temperatures will help prepare the amaryllises for winter.
Wait until the foliage turns yellowish brown. Indoor plants may only droop (or wilt).
Healthy, green leaves are still absorbing sunlight and converting it into sugar for plant food, which is stored in the bulbs.
Cut off the yellowish brown or wilting foliage with pruning shears or clippers. Cut them back to the ground, unless you have outdoor amaryllis plants and live in USDA hardiness zones 3 and 4. There, clip them back so a couple inches of foliage still remains.
Move potted amaryllises to a warm, dry and dark location (e.g., closet) until January, at which time you should move the pot back to a sunny location and begin to water and feed them again. Alternatively, if your amaryllises are planted outdoors, cover the planting site with several inches of mulch, especially in USDA hardiness zones 5 to 7. In zones 3 and 4, you will need to dig them up and store them for the winter (as described in Steps 5 and 6).
Dig up outdoor amaryllis bulbs in USDA hardiness zones 3 and 4. You should have left a couple inches of foliage on so you can see and handle your bulbs. Use a shovel or garden fork and dig a couple inches from the stem. Amaryllises are typically buried about eight inches beneath the soil, so dig about 10 inches to clear the bulbs. Push down on the handle of your shovel or garden fork in several spots to lift the bulbs out of the soil.
Store amaryllis bulbs in a cool dark location, such as a garage or attic, until after the last frost in zones 3 and 4. You can also store them in an open plastic bag in in the crisper drawer of the refrigerator. Do not store apples nearby which will cause the bulbs to become sterile and not bloom.