Frequently seen around the Christmas holiday, indoor forced amaryllis (Hippeastrum spp.) flower in winter, while those grown naturally outdoors bloom in spring or early summer. Amaryllis, which thrives outdoors in U.S. Department of Agriculture plant hardiness zones 8 through 10, grows from a large bulb that goes through a natural dormant period. Proper after-flowering care helps the bulb recover from the blooming period and prepares it for dormancy.
After flowering, the foliage of the amaryllis persists for several months. Removal of the old flower spikes promptly after the blossoms wilt allows the amaryllis to use its energy to focus on replenishing the nutrient stores in the bulb. The amaryllis continues to grow best at 65 to 70 degree Fahrenheit temperatures in an area with full, all-day sunlight. Twice-monthly fertilization with a potted plant fertilizer, such as 1/2 teaspoon of 24-8-16 fertilizer dissolved in 1 gallon of water, provides sufficient nutrition to fuel the bulb.
Amaryllis must go through a period of dormancy to rebloom. Withholding water and fertilizer in early fall forces the bulb into a dormant state. After the foliage dies back, it requires removal. You can leave the bulb in the pot or remove it and store it in dry peat moss. During dormancy amaryllis doesn't require any watering and water can cause the dormant bulb to rot. After eight to 10 weeks of dormancy the bulb is ready to plant and regrow.
The bulb benefits from fresh potting soil after the dormant period. Amaryllis grows best in a container 2 inches larger in diameter than the bulb. Pots should have a bottom drainage hole so the soil doesn't retain too much moisture. The bulb requires planting with one-third of the bulb sitting above the soil surface. After new growth resumes, water the soil when the surface dries and provide the plant with all-day sun. Resume fertilization when the bulb begins producing leaves.
Outdoor-grown amaryllis require care that is similar that of indoor potted plants. When grown outside, the amaryllis usually blooms in spring or early summer. The flowers are cut off after bloom, and the plant's foliage is left to continue growing. Water the amaryllis about once weekly to moisten the top 6 inches of soil. An application of 1/2 pound of 6-12-12 fertilizer per 50 square feet of bed immediately after flower removal refuels the bulb. The foliage usually dies back and the bulb goes dormant in late fall or early winter. The amaryllis requires no further care until it resumes growth in spring.
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