The amaryllis is among the most spectacular flowering bulbs for indoor gardeners.
Even during the winter season, when climate is cool and sun is sparse, the amaryllis flowers often reach 6 to 8 inches wide with several blossoms on a stem 8 to 12 inches long.
Amaryllis bulbs are availale from many retail outlets such as food stores, garden centers, greenhouses and stores such as Lowe’s and Home Depot. Flowering bulbs also are available as gift plants on various holidays.
The hybrid amaryllis grown indoors was developed from several species native to South Africa. Bulbs from these warm climates respond to wet-dry cycles rather than the cold-warm cycles associated with the spring flowering bulbs for outdoor planting.
Amaryllis bulbs may be purchased already potted or dormant and not potted. Normally, dormancy is brought on by dry conditions. After the leaves have died, as on bulbs saved from last year, bulbs should remain dormant for about two months before watering to promote new growth.
Growing your amaryllis
Culture of amaryllis is fairly simple. If you begin with dormant unpotted bulbs, always select the largest bulbs you can find. The planting container should be at least 2 inches greater in diameter than the diameter of the bulb.
The bulbs should be potted in a rich, well-drained soil mixture. A suitable potting soil might contain equal parts of good garden soil, well-composted cow manure and peat moss or compost. It is probably easier to purchase a commercially prepared potting soil.
To each 6-inch pot of potting soil, add about one tablespoon of bone meal. This material is a good source of phosphorous, needed to develop a strong root system. There is also some nitrogen and calcium in bone meal.
When planting a bulb, remove any dead or broken roots. Position the bulb so one-third to one-half of it is above the soil line. Fill in around any fleshy roots and firm the soil along the sides of the bulb.
After potting, water the bulb until water drains from the bottom of the container. There must be drain holes in the bottom to prevent accumulation of water that will rot the bulb before it can grow.
Next, place the potted bulb in a cool, lighted room, but not in full sunlight. Cool temperatures, about 55 degrees Fahrenheit, are ideal for root formation on the bulb. Warmer temperatures will cause top growth before the roots can really form. When top growth comes first, there may be longer leaves formed and weak-ened flower stalks later.
After the roots have formed and top growth is evident, move the bulb to a warmer location with temperatures of about 70 degrees for flowering. The soil should always remain slightly damp but never very wet.
Apply a liquid houseplant fertilizer about every three weeks, April though June, to maintain the vigor of the plant. When the plant is in bloom, keep it in bright light but avoid direct sun, which can heat the flower petals and shorten their life. Moving the plant to a cool temperature at night also helps to increase the life of the flower.
After flowering is complete, cut of the flower stalk and move the plant to a sunny indoor location until spring. It is important that the foliage be kept alive if you want to maintain the bulb over a period of years. The growing foliage feeds and strengthens the bulb for the next flowering cycle.
After danger of frost is past, in late spring, set the pot and bulb into the soil so the rim of the pot is level with the ground. A semi-shaded spot is best and will prevent sunburn of the foliage during the hottest parts of the summer.
Continue watering the plant during the summer so the foliage can rebuild the bulb. Once a week, rotate the pot a quarter turn to prevent the roots from growing through the drain hole and into the soil below. This will also help to keep the entire root system in the pot.
In the fall, move the bulb indoors before the first frost. Even light frost will injure the bulb and foliage, so it is important to be careful at this time of year.
Withhold water until the leaves dry and the bulb become dormant. After a minimum of eight weeks of dryness, the dormant period should be completed, and the bulb is ready to begin the growth and flowering cycle again. Failure to bloom the second or following seasons usually means that the plant did not produce enough growth during the past summer to support flower bud development.
At the end of the dormancy period, begin the watering and temperature program described for the start of a new bulb. Repotting may be necessary about every three years.
At the beginning of the second growing season, remove several inches of potting soil from the surface of the pot and replace it with fresh material. Also remove any dead foliage. Good luck and enjoy some great indoor color.
Bill Lamont is a professor and extension vegetable specialist in Penn State’s department of plant science and can be reached by email at email@example.com.