Often enjoyed as a winter holiday gift plant, amaryllis (Hippeastrum spp.) blooms are large and range in color from deep red to pink, salmon or white. With origins in tropical South America, these hybrid bulbs grow outdoors in USDA hardiness zones 8 and warmer and make good potted houseplants in regions with inhospitable climates. Healthy bulbs grown in warm, sunny spots produce the most flowers and foliage, leading to future reblooming episodes.
Amaryllis is a winter deciduous bulb, going dormant during the cool, dry winter months. In spring's warmth, the bulb sends up its flower stalk, followed thereafter by its many green straplike leaves. Once the flower dies, the leaves remain through the summer and early fall to make food to replenish and enlarge the underground bulb. By late fall this foliage naturally yellows and dies away. Mimicking this natural growth cycle ensures the amaryllis plant prospers in the garden or houseplant container.
Whether in the garden or a container, amaryllis should be grown in appropriate soil conditions. The most important soil quality is that it's well-draining and never stays soggy after watering. Sandy garden soils rich in organic matter make perfect settings and potting mixes must be made of roughly equal parts peat, perlite and coarse sand. An acidic soil is also best, in the pH range of 5.0 to 6.5.
Plant dormant amaryllis bulbs from the garden center as soon as possible following the guidelines for soil, planting considerations and watering. Plant the amaryllis bulb with the pointed tip upward at a depth of 2 to 4 inches, so that one-third to one-half of the bulb remains exposed. Do not plant the bulb too deeply. The "neck" of the bulb must always protrude out of the soil.
Provide 1 inch of rainfall or irrigation to the amaryllis bulb weekly when leaves or flowers are present. Apply a well-balanced liquid fertilizer according to product label directions as part of a normal watering every two weeks. In autumn, taper off watering frequency after the equinox and stop fertilization. The leaves slowly yellow and then die away. By late autumn, water every two to three weeks, keeping the soil barely moist. In midwinter, allow the soil to become almost bone dry to ensure the firm, healthy bulb does not rot. Once the flower stalk or new foliage emerges in spring, slowly increase watering back to 1 inch weekly and begin fertilizing when leaves are present.
Garden clumps of bulbs outdoors should be carefully dug up in autumn as the yellow foliage become nearly dead so you can locate the bulbs. Do not plant them too deeply and water the soil after the planting according to the time of year and presence of foliage.