The super-sized blooms of amaryllis (Hippeastrum) are hard to ignore. Every fall, stores are well-stocked with boxed amaryllis bulbs literally bursting at the seams, ready to grow. Though many may know amaryllis to be an indoor plant, in Zones 8 and south it can be grown outdoors as a spring-blooming bulb. And even though it’s not really a typical houseplant, we still let it hang around the house in the background, hoping it’ll rebloom to earn its keep.
In milder parts of the country, amaryllis can be grown outdoors as a spring-blooming bulb.
Photo Credit: Gerald Klingaman
Crowd several ‘Apple Blossom’ amaryllis bulbs together in a shallow bulb pot for greater visual impact.
Photo Credit: Gerald Klingaman
After receiving eight weeks of rest, these ‘Apple Blossom’ and ‘Red Lion’ amaryllis bloomed in 45 days.
Photo Credit: Gerald Klingaman
Part of the reason amaryllis hooks so many gardeners onto the hobby is that they’re so darn easy to grow. The boxed bulbs come complete with an enormous bulb, oftentimes pushing up a bloom spike while still imprisoned in the box. The growth of the flower stem can be measured in inches-per-day, and before you know it, the blooms appear in wonderful shades of red, including pink and orange, as well as white and bicolor (white and one of the red tones). Sure, if the plant were grown in a warm, dark room you may need a broom handle to keep it propped up, but by golly it bloomed!
That first blooming is the easy one because bulb dealers have been storing the fat amaryllis bulbs just below freezing since early spring, awaiting the lucrative holiday season. Getting amaryllis to rebloom a second time (especially if you’re hoping to hit a particular date) is trickier.
Only expect amaryllis bulbs to bloom once per year, and only bulbs larger than 2 inches in diameter are large enough to bloom at all. The bulbs that flowered in midwinter of one year won’t rebloom until at least a year later. But because amaryllis are typically spring-blooming plants, they’re easier to force into bloom in the February-through-April period than the November-through-January period.
Here’s what you need to know:
Like all bulbs, amaryllis goes through cycles of growth and rest. The formation of the floral scape (the stem that holds the flowers) occurs during late summer and fall, primarily as a response to good growing conditions and not because of some environmental signal such as shorter days or cooler temperatures. In studies I’ve done, it appears flower bud formation is complete by mid-September (imposing rest earlier than that delays blooming).
Once the flower buds have formed, the bulbs need to rest. Stop watering and allow the pots to dry, or if you’ve over-summered them in the flower bed, dig and allow the bulbs to dry in a cool, shaded area. Store the bulbs as close to 55 degrees F as possible. This is the optimum temperature for rest, and if you can provide it, eight weeks of storage will do the trick. (Higher or lower temperatures will also work, but the more you deviate from ideal conditions, add four to six weeks extra to the rest period.) Bulbs stored at colder conditions – for example 45 degrees F for 12 to 14 weeks – will bloom without their leaves, whereas those stored at the optimum conditions usually bloom with their leaves.
Once the rest requirement is satisfied, the bulbs are ready to force. Move the pots to a bright area with enough light to read a newspaper and begin watering about once a week. Normal room temperature conditions are ideal. If all has gone well, blooms should appear in around 45 days.
