Due to frequently being asked about this plant here are some tips on growing Amaryllis...
The Amaryllis bulbs on sale in Autumn are usually varieties of Hippeastrum and are similar to Amaryllis (Belladona Lily). Both are large bulbs which produce Lily like flowers on thick stalks.
Amaryllis flowers are smaller and appear after the foliage has died down. The other difference is that Hippeastrum (amaryllis) is an indoor plant whereas Amaryllis(Belladona Lily) may be grown out doors..
If it is Hippeastrum (Amaryllis), plant the bulb in compost and ensure the root does not dry out. Water sparingly until the shoot emerges. Water freely once in active growth and feed weekly. Hippeastrums generally bloom 8 weeks after planting. For Christmas flowers plant prepared bulbs in October.
Remove the flower stalk when blooms wither, discontinue watering and feeding when the leaves have gone yellow. Bring back into growth by starting to water after a period of rest. Repot every 3 years.