Hippeastrum is a genus of bulbous plants in the Amarylliceace family that produce showy flowers. They are commonly known as amaryllis plants, although technically that is the name of another genus. These types of flowers are frequently grown as indoor plants, or outdoors in flower beds in warmer climates. They are often given as gifts around the winter holidays. The bulbs require a rest period of cooler temperatures and can be forced into bloom whenever desired.
There are almost 100 species of Hippeastrum and hundreds of different varieties that are available in a range of colors, from red and pink to yellow to orange, among others. The flowers are quite large at between 5 and 8 inches (13 and 20 cm) across, and each 12 to 30 inch (30 to 75 cm) stem generally bears two flowers. The leaves are 1.5 to 3 ft (0.45 to 0.9 m) long, and the plants can spread to between 1 and 2 ft (0.9 and 1.8 m).
In the garden, these plants grow well in a variety of soils and usually bloom in the spring. The bulbs should be planted so that the top is just under the soil's surface. The amount of sunlight is the determining factor in whether the plants will flower well. They will flower best in full sun, although the foliage will become discolored. Hippeastrum plants are usually grown in some degree of shade, although they do not flower well in total shade.
Ideally, these plants should be kept moist and fertilized during their flowering period. Amaryllis plants do have some degree of drought tolerance. They are intolerant of salts in the soil, however.
For indoor blooms, the bulbs should be planted in pots that are 2 inches (5.2 cm) larger than the bulb, with one-third of the bulb being above the rim of the pot. They should be watered once thoroughly, then kept moist. It is very important to fertilize the plant once it has started to grow.
As indoor plants, the amaryllis should receive at least four hours of sun per day while the leaves are growing. The ideal temperatures are between 60 and 65°F (15.6-18.3°C) at night, and at least 70°F (21.1°C) during the day. When the plants are blooming, they should be kept cool and placed in indirect light.
As each flower fades, it should be cut off. After all of the flowers on a stalk are done blooming, one should remove the stalk just above the nose of the bulb. Often, Hippeastrum plants are kept to be grown and produce flowers again. If so, the plant or the bare bulb can be kept at 55°F (12.8°C) for about two months. Then, it should be grown at warmer temperatures.
As they age, Hippeastrum bulbs frequently develop small, new bulbs around the edges of the mother bulb. They can be left in place to produce a great number of flowers. These smaller bulbs can be removed at the end of the storage process and used to propagate new plants. It is also possible to grow new plants from seeds. The latter process usually takes several years.