(Technically, what are commonly called "amaryllis" are really species of hippeastrum.)
With luck, or if the bulbs were from South Africa, Brazil or greenhouses in Israel, you'll have blooms by Christmastime. That's because it's spring in the southern hemisphere, and effectively so in Israeli greenhouses.
Getting any amaryllis bulb in bloom a little later in winter is easy, but again, get the bulb ready now. And that's not hard, because most of what's needed is neglect.
Amaryllis bulbs flower best and most quickly after experiencing a cool period at the end of summer. So find a location where temperatures remain below 60 degrees but above freezing, such as in an unheated basement or garage, perhaps even outside for awhile, depending on your climate. This cool period sets the stage for the flower buds, already formed within the bulbs, to open. New bulbs that come from Holland may have already spent some time in refrigerated storage or transit.
During their cool period, the plants won't need any water at all. Contrary to myth, drying down the foliage by withholding water is not necessary before the plants can flower; withholding water does slow or stop new leaf growth, but those old leaves pretty much hang on, green. If you find the leaves unsightly or in the way, just cut them off.
REST PERIOD IS OVER
After about eight weeks of cool neglect, the bulb is refreshed. When you want flowers, offer warmth, light and water. The plant needs only a bit of water to get started growing, then increasing amounts once growth proceeds in earnest. Blossoms will unfold within four to five weeks at temperatures hovering around 70 degrees, more quickly at warmer temperatures and more slowly at cooler ones.
Playing around with the amount of cooling you give a particular variety of amaryllis sometimes influences whether flower stalks appear before or with new foliage. And some amaryllises — most notably the dainty Gracilis types — are especially easy to bring into earlier bloom. These dwarf amaryllises are so forgiving that you might even have to hold them to near-freezing temperatures just to keep them from flowering prematurely.
PREPARING FOR NEXT YEAR
After blossoms have come and gone, it's time again to start preparing an amaryllis for the following winter's blooms. Those flowers unfold from buds that form deep within the bulbs during spring and summer, so the better the growth during the warm months, the better the flowers the next winter. Your reward is one flower bud for every four to six leaves your bulb grows. Spur leaf growth with plenty of water, warmth, fertilizer and light.
Repot the bulb if it's getting cramped in its pot; tease some of the old soil away from the outside of the root ball, then pack the plant into a larger pot with fresh potting soil. An amaryllis bulb is prone to rotting, so should be set with only its bottom half in the soil, and the potting soil should be well-drained. A bulb can go for three or four years without repotting so long as there is an inch or so of space between the bulb and the rim of the pot.
When warm weather reliably settles in come spring, move your amaryllis outdoors to a partially shaded location. You can ease your watering chores by plunging the pot, if it is unglazed clay, up to its rim in the ground to absorb moisture from surrounding soil. Or tip the rootball out of the pot and temporarily plant the bulb outdoors.
Each year, let waning summer sun get you thinking again about getting your bulbs primed for the winter show. If you're in no rush for the flowers, forgo the cool treatment. Any amaryllis bulb will eventually flower with reasonable growing conditions.