December 17, 2016

1 - Cool, dry conditions are necessary to induce amaryllis (Hippeastrum) bulbs to bloom.

Yard and Garden December 17, 2016

Q.

Several years ago I received an amaryllis bulb. I planted it according to directions and was blessed with beautiful flowers. However, it has never produced flowers since then. It has grown long leaves, but no flowers. Is it possible to induce it to flower again? The first time it flowered it made a seed pod which I cut off and discarded. If I had let the pod mature would the seeds have produced new plants that would flower?

A.

The plants most often sold as amaryllis is probably the plant in the genusHippeastrum. The taxonomy of this plant is somewhat confused. There is a true genus Amaryllis, but that is a plant native to South Africa. The true Amaryllishas a solid flower scape (flower stalk) which bears more flowers than the hollow flower scape of the Hippeastrum which is native to South America. The Hippeastrumis the bulb most commonly sold in garden centers and through many mail order nurseries.

In order to encourage flowering in your Hippeastrum plants, you need to be sure to provide proper growing conditions during the spring and summer. This may mean repotting every few years into fresh potting soil in pots that allow at least 2 inches soil space between the bulb and the sides of the pot. You must also provide adequate moisture, sunlight, and fertility to promote good leaf development. Healthy leaves are necessary to sustain the health of the bulb and development of flowers. The bulb is composed of the enlarged bases of the leaves, so the healthier the leaves, the larger the bulb will become, and the more food will be stored in the bulb for development of flowers.

Healthy bulbs must become dormant under the influence of cool, dry, winter conditions to stimulate the initiation of flower buds. This may be the hardest part for most gardeners. Water must be withheld to the point that the leaves may shrivel, turn yellow, and fall off. Temperatures should be maintained between about 39 and 55 degrees for 8 to 10 weeks. The bulbs should not freeze, but a cool temperature is important. One year I left my plants outdoors a few hours too long. The leaves froze, but the bulbs did not. Those frozen leaves dried and dropped from the plants and I was rewarded with many beautiful, large flowers later that winter. I do not recommend letting your plants freeze.

Removing the seed capsules after the flowers fall helps maintain the vigor and size of the bulbs, but letting the seed mature to plant can be an interesting activity for gardeners. If the bulb is otherwise healthy, you can allow the seed capsule to mature. When it turns yellow and begins to split along the sutures in the capsule, you can harvest the seed. The seed inside the capsule will look somewhat like black corn flakes. They will be thin and papery with a swelling in the center. This swelling is the seed. Collect the seed and plant them in good potting soil. Keep them moist, but not soggy, and they should grow for you. Under good conditions they should begin blooming in about 5 years. Because the bulbs that are commercially available are hybrids, the resulting flowers will probably not look like the flowers that produced the seeds. When I have grown them from seeds, the resulting flowers have been smaller and orange in color even though the parents were red or white flowered amaryllis. In my case the originals were superior, but the challenge of growing amaryllis from seed was enjoyable.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

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