Paul A. Thomas, Extension Horticulturist
The large, bell-shaped or lily-like flowers of the amaryllis and its hybrids make excellent garden subjects and pot plants. They can be grown as garden plants from Macon southward in Georgia. In these areas, they are used in beds, borders and for specimen plants. In north Georgia, they make excellent pot plants and spring and summer garden plants.
When used as individual specimens, in mass plantings, as part of perennial borders or as low plantings in front of shrub borders, amaryllis provide spectacular flower effects. They have a wide range of flower colors from red, pink and white to combinations of these. Their large, robust flowers of beautiful textures add to their appeal.
When properly handled and cared for properly, an amaryllis bulb may produce flowers for up to 75 years. Good quality bulbs of named varieties may produce up to six flowers on a single stalk.
When grown in containers, amaryllis prefer a sandy-loam soil mix. You can mix your own by combining one part leaf mold or composted manure, one part loamy soil, and one part coarse sand. Some garden centers also sell soil mixes especially for bulbs. The mixture should be slightly acid, with a pH of 6.0 to 6.8.
Potting can be done anytime after the plants have gone through a dormant or rest period, which is late summer or early fall. Late October is thought to be an ideal time. Make certain bulb and soil are dry before repotting. Off-shoots can be removed and repotted separately at this time.
Use a small pot in relation to the bulb size. Many gardeners prefer a four inch pot or a shallow azalea-type pot. A pot is generally considered large enough if there is room for an inch of soil between the inside edge of the pot and the bulb. Place two or three pieces of broken clay flower pot or 1/2 inch of gravel in the bottom. Amaryllis like to be slightly rootbound.
When potting, add enough soil so that one-half to two-thirds of the bulb neck is above the soil surface. Leave 1/2 to one inch of space between the soil surface and the rim of the pot to facilitate watering. A thorough watering is essential immediately after potting. Maintain the bulb in a slightly moist soil condition until flowering. When flowering starts, increase the frequency of waterings to prolong flowering.
Container-grown amaryllis can be transplanted outside as soon as the danger of frost has passed.
Amaryllis will grow in almost any good garden soil as long as it is well-drained. An elevated bed (6 to 12 inches above the existing grade) may be necessary to assure good drainage. A soil rich in organic matter will provide best growth.
Ideally, late September or early October is the recommended time for planting outdoors. If you are transplanting bulbs from older crowded beds, transplant them in fall when the foliage turns yellow and begins drooping (a natural process at the end of the growing season).
Plant bulbs about a foot apart leaving the tops barely covered with soil. Mulch the planting to conserve moisture and to help control weeds. In central Georgia, you can overwinter the bed with a heavy layer of mulch for winter protection.
When growing amaryllis as a pot plant in the home, a southern window exposure provides ideal conditions for sun-loving amaryllis. An eastern or western facing window is second best, while plants grown in a northern window may require supplemental light. Light from a 100-watt bulb provided for a few hours each evening should be sufficient.
Amaryllis prefers a warm temperature (70 degrees to 75 degrees F) for best growth. However, once the plant flowers, cooler temperatures (65 degrees F) will extend the length of bloom. You can expect plants to bloom six to eight weeks after planting indoors, depending on temperature, light and variety. More time is required for plants to bloom outdoors.
Fertilization determines the size and quality of the flowers and foliage. Any soluble or liquid fertilizer is satisfactory for pot plants, but use it at half the recommended rate. Apply liquid fertilizers at five to six-week intervals.
On garden plantings, use fertilizers containing low nitrogen, such as 5-10-10 or 6-12-12 analysis. A bulb booster type fertilizer can also be used. Avoid applying excess nitrogen because it promotes vegetative growth and reduces flowering.
If you use a 5-10-10 or 6-12-12 analysis, apply one to 1-1/2 pounds per 100 square feet or bed space or 100 feet of row to established plantings, or three pounds per 100 square feet on new plantings.
Make the first fertilizer application as new growth begins, then repeat the application when the flower stem is six to eight inches tall. Apply a third application immediately after flowering when the old flower heads and flower stems have been removed.
As soon as each flower passes its peak beauty and begins to fade, remove it by cutting the flower stalk two inches from the base. This will prevent a drain of food from other developing flower beds or foliage. Don't disturb the foliage because it produces the food for next year's flowers.
To prepare potted amaryllis for flowering next year, stop watering and feeding the plant by October 1. When the foliage wilts and droops, cut it off. Then place the pot in a warm dry place until January. Do not water or fertilize during this rest period. Then move the pot to a southern window, begin watering and fertilizing, and the flowering cycle will start again.
Garden plants should be checked frequently for insects and diseases. "Red blotch" or leaf scorch disease is quite common. It appears as red spots on leaves, flower stems and flowers. Leaves or stems may be deformed and the bulb may have large, red blotches which rot easily.
Prevention and Control: Before planting, spray or dust bulbs with Captan or Benlate fungicide. If red blotch symptoms develop during the growing season, spray weekly or at 10-day intervals with Benlate or Captan to help reduce the severity of the disease. See your county Extension agent if you have questions or concerns about pesticide application and use.
Amaryllis are not generally attacked by insects. Grasshoppers are sometimes a problem on amaryllis grown outdoors.
Trimming flowers to bloom at a specific time is almost impossible. Complete failure of the plant to flower, small flowers or poorly formed flowers, may result from several conditions:
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