Shady conditions, overfertilization and overwatering can cause an amaryllis (H__ippeastrum spp.) to produce leaves but no flowers. Other reasons for nonblooming in an amaryllis include lifting the bulb too soon and a dormancy period that's too short. Amaryllis is hardy in U.S. Department of Agriculture plant hardiness zones 8 through 10. In colder zones, it's often grown as a houseplant.
Indoors and outside, an amaryllis needs bright conditions for flowering. Place an amaryllis houseplant near a window that receives morning sunlight and remains bright in the afternoon but doesn't receive direct light at that time.
Grow an outdoor amaryllis in bright shade or in a spot that receives dappled sunlight, such as under a tree.
Nutrients and Water
Rich soil or excess fertilizer or water encourages lush leafy growth and no flowers in an amaryllis. Grow an outdoor amaryllis in average, freely draining soil, and grow an indoor plant in general-purpose, freely draining potting soil in a container with drainage holes.
An amaryllis in a container doesn't need fertilizer until after the flower bulb appears. Fertilize the garden bed before planting an outdoor amaryllis. Evenly sprinkle a ready-to-use, 6-6-6, slow-release fertilizer at a rate of about 3 ounces per 10 square feet. Mix the fertilizer into the soil to a depth of 6 inches. Don't fertilize the amaryllis again before flowering.
An established outdoor amaryllis tolerates drought. Water an outdoor plant when the soil is dry to a depth of 2 to 3 inches. Apply water until the soil is moist to the depth of the bulb roots. Overwatering an amaryllis houseplant can cause bulb rots. Water an indoor plant after planting in its container, and don't water it again until you can see the roots through the drainage holes. Water an indoor amaryllis when the potting soil is dry to a depth of 1 inch. Pour water into the container until it flows through the drainage holes.
Lifting an outdoor amaryllis, or removing an indoor plant from its pot, too soon prevents the plant from storing up energy for flowering the following year. An in-ground amaryllis should not be lifted for winter storage until fall, when the foliage naturally dies down. An indoor plant can be placed outdoors when the final average frost date has passed or grown indoors for the rest of the growing season. Bring an amaryllis in a container inside before the first average frost date in fall.
An amaryllis that doesn't experience at least two months of dormancy won't flower. A dormant amaryllis is a bulb. Its leaves and roots have dried and withered away. Usually this happens naturally at the end of the growing season.
Dig up an outdoor amaryllis and place it in a dry shady place for eight weeks before replanting it. Place an indoor plant in its container in a dry place at temperatures between 40 to 45 degrees Fahrenheit.