Few plants can top the amaryllis (Hippeastrum spp.) for impressive, showy flowers. The plant grows from a large bulb that can only stay outdoors year-round in U.S. Department of Agriculture plant hardiness zones 8 or 9 through 11. This plant is often grown indoors in a pot, started in summer or fall -- called forcing -- to bloom indoors during the holiday season. You can grow an amaryllis as an annual, trimming it for neatness while it's blooming and then discarding it, but with a little extra care it can bloom again and continue blooming for years.
Amaryllis blossoms develop on the upper end of a tall, stiff stalk, with each bulb ultimately producing up to seven lily-shaped flowers that can be 6 inches or more across. All the flowers open in sequence on this stalk, with some flowers fading before other buds have opened. Cutting each flower off as it fades -- called deadheading -- can help keep the plant looking tidy. Because the flowers all originate from the same point on the stem's tip, cutting away old blooms can also make it easier for new flowers to open fully.
To trim the flowers away, use small sharp shears, cleaning your blades by wiping them with rubbing alcohol between each cut to prevent the spread of plant diseases. Be careful not to break off any of the smaller, unopened buds on the stem when trimming faded flowers.
Cutting the Stalk
When all the flowers on a stalk have withered, it's time to cut off the entire flower stalk with shears, making the cut about 1/2 inch above the top of the bulb. An extra large bulb might develop two or three flower stalks, each with buds; cut these off in sequence as the flowers fade.
An amaryllis flower stalk drips fluid from the cut end and can be messy.
Caring for Foliage
When the amaryllis has produced all its flowers, long green, straplike leaves remain. Place the plant in a sunny window and water it whenever the top 2 inches of soil feel dry to the touch. This period of leaf growth allows the bulb to store nutrients for the next season's bloom. If your plant bloomed during winter, keep it indoors until outdoor temperature stays above about 50 degrees Fahrenheit, and then move it outdoors to a sunny spot.
If the bulb is in a pot without a drainage hole, remove it from the pot and replant it in a well-draining pot before taking it outdoors or set it in the garden for the summer, with the bulb's "shoulders" just above the soil line.
As summer progresses, leaves on an amaryllis gradually turn yellow as the plant slows its growth. When this happens, stop watering and allow the soil to dry out and leaves to wither naturally. Once they're dry, cut off all the leaves about 1 inch above the bulb and place the pot indoors in a dry, dark place such as a basement or a closet. After the plant's been dormant for about eight or 10 weeks, replace the old soil with fresh potting soil, place the pot in bright light, and resume watering to start new growth.
If you live in USDA zones 9 through 11, you can leave an amaryllis bulb in the ground through winter, but mulch the area to provide protection against cool weather and mark the spot with a labeled stick. Mulch is particularly important if you want to leave the plant outdoors through winter in USDA zone 8. Otherwise, trim the plant as you would a potted amaryllis.