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Among indoor flowering plants, few can match amaryllis in grandeur. Its blooms are spectacular in size and come in many colors including bright, cheerful red. In addition to being very colorful, it has the added attraction of being relatively easy to re-bloom and can continue to give pleasure to its recipient for many years. For those who might have received an amaryllis for Christmas, now is the time to start the care it needs to provide beauty next year.
The plant commonly sold as amaryllis actually is misnamed and is a member of the genus Hippeastrum, not Amaryllis. Hippeastrum is native to the tropical Americas whereas the true Amaryllis is native to Africa. Both are members of the Amaryllidaceae plant family. "Hippeastrum" comes from the Greek word meaning "horseman's star"; a name most likely selected for this plant because of the resemblance of its flowers to a star-shaped medieval weapon used by horseman. For simplicity's sake we will continue to refer to the plant as amaryllis in this article.
Most of the amaryllis sold today are hybrids developed by the Dutch and were selected for their huge, showy flowers and forcing ease. It is not unusual for a vigorous bulb to produce up to six flowers, four to six inches in diameter, per scape (flower stalk). Since amaryllis is native to the subtropical and tropical Americas, their tender nature forces us to treat them as greenhouse or house plants here in the Midwest.
If you received a flowering amaryllis plant during the holidays, keep its growing medium uniformly moist. Small bulbs may produce only one scape, while large bulbs may produce two or three. After the last flower fades, cut off the scape(s) and place the plant in a bright location, if you are interested in having it bloom again next year. Fertilize the plant with a houseplant fertilize according to label directions and allow the leaves to continue to grow.
If a bulb was received instead of a flowering plant, amaryllis production for the hobbyist is relatively straight-forward. Plant the bulb in a well-drained, highly organic potting mix that retains adequate moisture. A mixture of sphagnum peat, vermiculite and perlite works well. Maintaining this medium in a slightly acid state is desirable. Containers often are furnished with the amaryllis bulb in a kit. If such was not the case, choose a container at least two inches wider than the diameter of the bulb.
The bulb received as a gift already will have a scape formed inside. Exposure to moisture and proper temperatures will cause this scape to elongate, mature and flower. Since amaryllis is tropical by nature, plants respond well to high temperatures (both day and night). A minimum of 70 degrees F. during the day and 60 degrees at night is ideal during the growth cycle of the plants. Temperatures lower than 50 degrees can be injurious and should be avoided. Amaryllis requires, on the average, from six to eight weeks from the beginning of growth to the production of flowers.
Re-blooming amaryllis is relatively easy, but the plant must be allowed to manufacture and store food in its bulb in preparation for the process. This is accomplished by exposing the plant to light as bright as possible during the growth period that occurs after flowering has ended. Adequate water and fertilizer are essential for maximum food production during this period. After the danger of frost has past, moving the plant outdoors into a lightly shaded setting will facilitate growth and improve subsequent blooming.
In September, the plant should be brought indoors and water withheld. This will induce dormancy, which should be maintained for several months. During its dormant phase, an amaryllis should be kept on the cool side and should not receive water. The leaves will wither and dry during this phase and may be removed.
The growth cycle (along with blooming) can be repeated by forcing the plant out of dormancy by watering and subjecting it to warm temperatures as described above. Repotting may be necessary if the bulb has outgrown its original container.
Failure to flower one season does not necessarily mean the plant will not produce flowers the next season. However, failure to flower does mean that growing conditions were not adequate and corrective steps must be taken. Elongated, pale-looking leaves on a flowerless plant is indicative of inadequate light intensity, temperatures that are above optimum or, perhaps, a combination of both.
Amaryllis is a bit easier to re-bloom later in the winter. If there is no need or desire to have the plant in flower for the holidays, allow it to grow outdoors as late as possible in the fall. Do not, however, allow it to be exposed to cold temperatures. Bring the plant indoors before frost, withhold water and allow the leaves to fall off. Place the dormant plant in a bright location and start watering again in January or February for late-winter or early spring flowers.
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REVISED: February 21, 2017