These fall into two horticultural classes, which might be called “deciduous” and “evergreen.” Both produce masses of color in borders, bearing clustered flowers at the tops of leafy stems. The flowers, brightly colored and marked with contrasting blotches and flecks, are superb cut flowers and a favorite with florists for their lasting quality. Plants appreciate good drainage. Mulch deeply where winters are severe.
Deciduous types. For many years, deciduous alstroemerias were the only ones readily available as garden subjects. The seed-grown Ligtu hybrids and Dr. Salter’s hybrids have azalea-like flowers in beautiful, edible-sounding colors—orange, peach, shrimp, salmon—as well as red and near-white; all types are flecked and striped with deeper colors. They produce leafy shoots 2–5 ft. tall in late winter and into spring; as these shoots begin to brown, the flowering shoots appear, with blooms following in early to midsummer. If allowed to set seed, they will self-sow. Plants go dormant after bloom and need no water unless winter rains fail. They naturalize where winters are not severe. Sow seeds in fall, winter, or earliest spring, either where plants are to grow or in pots for later planting out.
Evergreen types. Evergreen alstroemerias include two species and a number of hybrids. The hybrids, available in various colors, were once grown only by commercial florists, who jealously guarded their plants from the home gardening public. American breeders have now produced similar hybrids, which are offered as potted plants. These will produce flowering shoots as long as the soil does not get too warm; repeat bloom can be stimulated by pulling up flowering shoots from the base rather than cutting them.
These evergreens include series such as Meyer, Premier, Inca, and Princess (which is particularly compact and free blooming). Hybrids vary in height and come in many colors, mostly in the purple-pink-red range with dark flecks. These plants are usually sold by color, so buy them in bloom to be sure of what you’re getting. New hybrids show up constantly; check with local nurseries for availability. Some are root-hardy to 0°F (–18°C). Most hybrids will produce flowering shoots as long as the soil does not get too warm.
Repeat bloom can be stimulated by pulling up flowering shoots from the base rather than cutting them. The best way to do that: grasp each flower several inches above the soil and gently twist and pull upward to break the stem’s base cleanly away from the rhizome. The best times to pick are in the cool months (spring and fall), when plants are growing best.