Alstroemeria, commonly known as the Peruvian Lily, is a perennial prized for its vibrant, orchid-like blooms and extended flowering season. These South American natives bring color to garden beds and containers, often blooming continuously from late spring until the first frost. The flowers are famous for their exceptional longevity in a vase, making them a favorite among florists and home gardeners. Understanding the specific needs of this tuberous plant ensures a robust display of color year after year.
Site Selection and Soil Preparation
Alstroemeria thrives best when positioned to receive full morning sun, followed by protection from the intense heat of the afternoon. In regions with hot summers, providing partial shade during the hottest part of the day prevents foliage scorching and helps prolong blooming. Adequate light exposure is necessary for strong stem development and abundant flower production.
The planting medium directly influences the health of the plant’s fleshy tubers. Well-draining soil is necessary to prevent waterlogging, which can lead to tuber rot. The ideal soil pH for Peruvian Lilies ranges from slightly acidic to neutral, generally between 5.5 and 7.0.
Incorporating organic matter, such as compost or aged manure, improves drainage in heavy clay soils and moisture retention in sandy soils. When planting bare tubers or potted specimens, ensure the crown is set six to eight inches deep in the prepared soil. This depth helps insulate the tubers from temperature fluctuations and provides anchorage for the tall stems. Spacing plants 18 to 24 inches apart allows for adequate air circulation and clump expansion.
Watering and Fertilization Schedule
Consistent moisture levels are important for Alstroemeria, especially during active growth and blooming. The goal is to keep the soil evenly moist without allowing it to become saturated or waterlogged. Deep watering encourages the development of a strong root system, which supports the plant’s vigorous growth.
Allowing the top inch or two of soil to dry slightly between watering sessions helps maintain the balance between moisture and aeration around the tubers. Periods of drought or inconsistent watering can lead to reduced flowering and premature dormancy. Monitoring soil moisture is a more reliable method than adhering to a fixed schedule.
A balanced, slow-release granular fertilizer applied in early spring provides a steady supply of nutrients as the plant emerges from dormancy. During the peak blooming period, supplementing with a liquid feed higher in potassium every four to six weeks supports flower development. Potassium strengthens stems and enhances bloom quality.
Avoiding fertilizers with excessive nitrogen content is important, as this promotes lush, leafy growth at the expense of flower production. Over-fertilization can lead to weak, floppy stems that are unable to support the flowers. A light, consistent feeding regimen is more beneficial than infrequent, heavy applications.
Pruning and Deadheading Techniques
The method used to remove spent flowers is unique to Alstroemeria and significantly impacts reblooming potential. Instead of cutting the faded flower stem with shears, the entire stalk should be gently grasped near the base of the plant. The stem is then pulled sharply upward, ensuring it separates cleanly from the underground tuber.
This pulling action stimulates the tuber to produce new flowering shoots, encouraging a continuous cycle of blooms. Cutting the stem above ground leaves a stub that can rot and does not send the signal to the tuber for regeneration. This technique prevents the plant from diverting energy into producing seeds, which signals the end of the flowering cycle.
Beyond deadheading, structural maintenance involves removing any yellowed, damaged, or dead foliage. This pruning improves air circulation around the base of the plant, which helps mitigate the risk of fungal diseases in dense clumps. Maintaining an open structure ensures that light reaches the lower parts of the plant, promoting overall health.
The pulled stems can be composted, but the primary benefit of this technique is the direct physiological response it elicits from the root system. Consistent application of the pulling method is the most effective way to maximize the number of flowers produced by the Peruvian Lily.
Winter Care and Dormancy
Alstroemeria is considered a tender perennial, reliably hardy in USDA zones 7 through 10. Preparing the plant for dormancy depends on local climate conditions. In regions where winter temperatures consistently drop below 20 degrees Fahrenheit, the tubers require protection.
Gardeners in colder zones (zone 6 and below) should lift the tuberous roots after the first hard frost causes the foliage to die back. The lifted tubers should be cleaned, allowed to dry slightly, and stored in a cool, dark, frost-free location, ideally between 35 and 40 degrees Fahrenheit. Storing them in peat moss or sawdust prevents freezing and ensures survival until replanting in the spring.
In milder climates (zone 7 and warmer), the plants can remain in the ground. The dead foliage should be cut back to ground level once it has yellowed, signaling the onset of dormancy. Applying a thick layer of organic mulch, such as straw or shredded leaves, over the planting area provides insulation against cold snaps and helps stabilize soil temperatures. This protective layer should be removed in early spring as new growth emerges.