How to Grow Amaryllis Outdoors

In freely draining soil and sunny or partially shaded spots, amaryllis (Hippeastrum spp.), grow fuss free. In warm climates, they can be left in the ground over winter. Amaryllis are hardy in U.S. Department of Agriculture plant hardiness zones 8 through 10. Hardiness zones are geographical areas where plants can grow outdoors year-round. In colder USDA zones, amaryllis should be outdoors only during the growing season, when no frosts threaten. These are amaryllis planting zones.

Amaryllis flowers are bell shaped, and colors include white, pink, orange, salmon, red and bicolored. The leaves are straplike and appear when the flowers open.

Amaryllis grow in most soil types, and they thrive in bright or dappled shade, such as underneath a tree. Growing spots that have organically rich soil and receive afternoon shade provide the best results. If your soil drains poorly, grow amaryllis in raised beds or large containers.

Devoting a large area of a garden bed or border to amaryllis is worth it. Groups of 10 or more amaryllis of the same variety give the best effect. Space amaryllis bulbs 12 to 15 inches apart.

Vivid amaryllis flower colors look good against an evergreen shrubbery background, and dark colors are most easily seen against a light background, such as a whitewashed wall.

Established amaryllis are drought resistant, but newly planted and mature bulbs perform best with regular watering. Water amaryllis when the soil is dry to a depth of 1 to 2 inches. Apply enough water to moisten the soil to the depth of the bulbs.

Spreading mulch around amaryllis when the shoots appear in spring conserves soil moisture and controls weeds, which compete with amaryllis for water. Spread a 2-inch layer of leaf mold, garden compost, shredded bark or another organic mulch over the bare soil, but avoid the amaryllis stems and leaves.

Don't grow amaryllis where the bulbs may completely dry out.

Fertilizing amaryllis with a low-nitrogen fertilizer encourages healthy growth and flowers. Apply a 5-10-10 or 6-12-12 ready-to-use fertilizer at a rate of 1 pound per 100 square feet, or about 1 1/2 ounces per 10 square feet. Evenly sprinkle the fertilizer on the soil when new shoots appear in spring, when the flower stems are 6 to 8 inches tall and again when the flowers have faded. Water the fertilizer into the soil.

Don't allow fertilizer to contact amaryllis flower stems or leaves. Rinse away any that accidentally lands on the plant.

In USDA zones 7 and lower, amaryllis must be lifted in fall to prevent frosts from damaging the bulbs. In warmer zones, digging up established beds eases congestion and reveals unhealthy, diseased bulbs, which can be discarded.

Lift amaryllis bulbs when the foliage begins to wilt and turn yellow or brown. Push a garden fork into the soil 3 or 4 inches from the base of the plants, and lever the fork upward, easing the bulbs out of the soil.

Store amaryllis bulbs in a dry, dark, frost-free area until spring.