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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Growing the Spectacular Amaryllis

This article was published originally on 10/12/2001

Amaryllis are popular flowering bulbs which are forced indoors for their large, spectacular blooms during the winter months. The trumpet- shaped flowers can be as large as 8 to 10 inches across. Flower colors include red, pink, orange, salmon, white, and bicolors (mostly whites with pink or red flushes). Two to six flowers (the average is four) are produced atop an 18- to 30-inch-tall flower stalk.

Forcing Amaryllis

Amaryllis bulbs can be purchased pre-planted in pots or unpotted. When purchasing amaryllis, select large, solid bulbs. The largest bulbs often produce 2 flower stalks.

Excellent varieties include: 'Red Lion'--deep crimson red, 'White Christmas'--snow white, 'Apple Blossom'--soft pink and white, 'Prince Carnival'--white with red stripes, 'Minerva'--red with white star, 'Picotee'--white with red edge, and 'Green Goddess'--white with a green throat.

Double-flowering amaryllis are also available. Varieties with double flowers include 'Pasadena'--red flower with white streaks, 'Lady Jane'--rose-pink flower with white streaks down the center of each petal, and 'Double Picotee'--pure white flower with red edges around the petals.

When planting an amaryllis bulb, select a pot which is approximately 1 to 2 inches wider than the diameter of the bulb. The container may be clay, ceramic or plastic, but should have drainage holes in the bottom. Plant the bulb in good, well-drained potting soil. Add a small amount of potting soil in the bottom of the pot. Center the bulb in the middle of the pot. Then add additional potting soil, firming it around the roots and bulb. When finished potting, the upper one- half to two-thirds of the bulb should remain above the soil surface. Also, leave about one inch between the soil surface and the pot's rim. Then water well and place in a warm (70 to 75 F) location.

Check the pot before watering a pre-planted amaryllis bulb. If the container doesn't have drainage holes, remove the bulb. Drill small holes in the bottom of the container and replant or transfer the bulb to a pot with drainage holes.

After the initial watering, allow the soil to dry somewhat before watering again. Keep the soil moist, but not wet. When growth appears, move the plant to a sunny window and apply a water-soluble fertilizer ever 2 to 4 weeks.

During flower stalk elongation, turn the pot each day to keep the flower stalk growing straight. Flower stalks that lean badly may need staking.

Flowering usually occurs about 4 to 6 weeks after potting. When the amaryllis begins to bloom, move the plant to a slightly cooler (60 to 65 F) location that doesn't receive direct sun to prolong the life of the flowers.

Pot amaryllis bulbs in early to mid-November for bloom during the Christmas holidays.

Care After Flowering

After the flowers fade, cut off the flower stalk with a sharp knife. Make the cut 1 to 2 inches above the bulb. Don't damage the foliage. In order for the bulb to bloom again next season, the plant must replenish its depleted food reserves. The strap-like leaves manufacture food which is stored in the bulb. Place the plant in a sunny window and water when the soil surface is nearly dry. Fertilize every 2 to 4 weeks with a houseplant fertilizer.

The amaryllis can be moved outdoors in late May or early June. Harden or acclimate the plant to the outdoors by placing it in a shady, protected area for 2 to 3 days then gradually expose it to a few hours of direct sun. Once hardened, dig a hole in a partially shaded or sunny flower bed and set the pot into the ground. Outdoors, continue to water the plant during dry weather. Also, continue to fertilize the amaryllis once or twice a month through July. Bring the plant indoors in mid-September. Plants left indoors should be kept in a sunny window.

Amaryllis bulbs need to go dormant or rest for 2 to 3 months before blooming. To induce dormancy, place the amaryllis in a cool, semi-dark location in late September and withhold water. Cut off the foliage when the leaves dry and turn brown. Then place the pot in a cool (40 to 50 F), dry location for a 2 to 3 month rest period. After several weeks of rest, periodically check the bulb for signs of new growth. When a bud or foliage begins to emerge, place the amaryllis in a warm, bright location and water to start the growth cycle again. If repotting is necessary, do so before watering. Large, healthy bulbs will produce 1 or 2 flower stalks. Small, weak bulbs produce only foliage.



This article originally appeared in the October 12, 2001 issue, pp. 114-115.

Year of Publication: 
2001
Issue: 
IC-485(23) -- October 12, 2001