Yard and Garden: Growing Amaryllis

These flowering bulbs are brought indoors for large winter blooms

September 21, 2020, 2:22 pm | Richard Jauron

AMES, Iowa -- Amaryllis are popular flowering bulbs that 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. In this Yard and Garden entry from Iowa State University Extension and Outreach, horticulture specialist Richard Jauron explains how amaryllis should be handled in the fall.

My amaryllis has been outdoors all summer. When should I bring it indoors and how do I get it to bloom?

Bring the amaryllis indoors in late September (before the first frost or freeze in fall). In order to bloom, amaryllis bulbs must be exposed to temperatures of 50 to 55 degrees Fahrenheit for a minimum of 8 to 10 weeks. This can be accomplished by inducing the plant to go dormant and then storing the dormant bulb at a temperature of 50 to 55 F.

flowering amaryllis.To induce dormancy, place the amaryllis in a cool, semi-dark location when the plant is brought indoors in late September. Withhold water. Cut off the foliage when the leaves turn brown. Then place the dormant bulb in a 50 to 55 F location for at least eight to 10 weeks. After the cool requirement has been met, start the growth cycle again by watering the bulb and placing it in a well-lit, 70 to 75 F location. Keep the potting soil moist, but not wet, until growth appears. The other option is to place the plant in a well-lit, 50 to 55 F location in late September. Maintain the amaryllis as a green plant from fall to mid-winter. After the cool requirement has been met, move the plant to a warmer (70 to 75 F) location.

How do you force an amaryllis bulb indoors?

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

When planting an amaryllis bulb, select a pot that 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 a well-drained potting mix. Place a small amount of the potting mix 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 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 thoroughly and place in a warm (70 to 75 F) location.

Check the pot before watering a pre-planted amaryllis bulb. If the container does not 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, water just enough to keep the potting mix barely moist. When growth appears, move the plant to a sunny window and water more frequently. During flower stalk elongation, turn the pot daily to keep the flower stalk growing straight. Stake flower stalks that lean badly.

When the amaryllis begins to bloom, move the plant to a slightly cooler (65 to 70 F) location that does not receive direct sun to prolong the life of the flowers.

When should I pot up an amaryllis bulb in order to have it in bloom at Christmas?

Most amaryllis bulbs are grown in South Africa and the Netherlands. South African-grown amaryllis bulbs typically bloom three to five weeks after potting. Cultivars commonly grown in South Africa include ‘Blushing Bride,’ ‘Inferno,’ ‘Lemon Sorbet,’ ‘Merry Christmas,’ ‘Rozetta,’ ‘Snow White’ and ‘Wedding Dance.’  Dutch-grown amaryllis bulbs typically bloom six to eight weeks after potting. Cultivars commonly grown in the Netherlands include ‘Aphrodite,’ ‘Apple Blossom,’ ‘Baby Star,’ ‘Christmas Gift,’ ‘Dancing Queen,’ ‘Minerva,’ ‘Naranja,’ ‘Neon,’ ‘Picotee,’ ‘Red Lion’ and ‘White Nymph.’

For more information, Jauron can be reached at rjauron@iastate.edu or 515-294-3108.


Original photo: amaryllis.

About the Authors: