It's difficult to be sure when an amaryllis bulb will flower. Just looking at the bulb there's no way to know when it's getting ready to sprout. And once they do start growing, some bulbs come into flower more quickly than others. But there are actually some clues to this mystery that can help you plan for the best possible results.
Amaryllis bulbs that are grown in the southern hemisphere (Brazil, Peru, South Africa), typically flower in December or early January. These are known as "early" or "Christmas blooming" amaryllis. Bulbs that are grown in Holland bloom later, usually starting in late January and continuing through March.
Like most bulbs, amaryllis go through a dormancy period that lasts between 3 and 6 months. During this time, the plants finish developing their flowers, using energy they stored during the growing season. Natural dormancy periods vary, which is why some varieties of amaryllis bloom before others.
When considering the lists below, note that some varieties of amaryllis are grown in both the northern and southern hemisphere. If you want bulbs that will bloom for the holidays, make sure they were grown in the southern hemisphere and plant them as soon as possible -- definitely before mid-November.
Note that some varieties of amaryllis are grown in both the northern and the southern hemispheres. So you can't go only by the variety name. But you can assume that most amaryllis are grown in the north and will flower in mid-winter. Bulbs that were grown in Peru, South Africa and other southern hemisphere locations, will usually call out the fact that they are early-blooming.
Another factor that impacts bloom time is when you plant the bulb. As a general rule, the sooner you put an amaryllis bulb into moist soil and give it light and warmth, the sooner it will wake up and start growing. But you'll also find that as the winter progresses, the bulbs are more eager to bloom and will come into flower more quickly.
If you purchase a number of amaryllis bulbs, you can extend their bloom times by not planting the bulbs all at once. Store the dormant bulbs in a cool, dry, dark place until you are ready to pot them up. Allow 6 to 10 weeks from planting to the first flowers.
How will you know when your amaryllis is starting to wake up? The first sign of growth will be the tip of a bud or a leaf peeking out from the top of the bulb. If the bulb hasn’t already been potted up, do it now and put the pot in a bright room that’s approximately 65-70°F. Water sparingly, which means no more than 1/4 cup per week. Once the bulb has sprouted and is in active growth, you can usually expect to see flowers in 3 to 4 weeks.
Amaryllis bulbs are somewhat unpredictable and may refuse to sprout until they're good and ready. Be patient. As long as you don't overwater and the bulb stays firm, it will eventually bloom.
Some bulbs send up their flower stalks before producing any leaves. Others send out leaves first, followed by the flower stalks. And sometimes you'll get leaves and flowers at the same time. Depending on the size of the bulb, you can expect to get between one and three flower stalks. Again, these may emerge all at once, or over a period of 3 to 4 weeks.