Calla lilies (Zantedeschia) are popular ornamental plants, known for their elegant, trumpet-shaped blooms and lush foliage. Their distinctive flowers, which come in a wide range of colors, enhance gardens and floral arrangements. Understanding their growth stages helps gardeners provide optimal care, ensuring these plants thrive and produce abundant blooms.
From Rhizome to Sprout
The journey of a calla lily begins with its rhizome, a modified underground stem that stores nutrients. Plant calla lily rhizomes in spring after the danger of frost has passed, when soil temperatures consistently reach at least 65°F (18°C). Choose a location with well-draining, organically rich soil, as soggy conditions can lead to rot. Plant the rhizomes approximately 3 to 4 inches deep, with the growing tips or “eyes” facing upwards. Space them about 12 inches apart.
Water thoroughly after planting to settle the soil around the rhizomes. Avoid overwatering, especially before shoots appear, to prevent rot. The first green shoots typically emerge within two to four weeks of planting, signaling visible growth. A healthy sprout indicates successful establishment and the beginning of the plant’s active life cycle.
Vegetative Growth
Following the emergence of sprouts, calla lilies enter a period of rapid vegetative growth, focusing on developing a robust root system and expanding their foliage. During this stage, the plant channels energy into producing large, often sword-shaped leaves that can be solid green or speckled with white. Strong foliage supports the plant’s ability to photosynthesize and store energy within the rhizome for future blooms.
Maintain consistent moisture; the soil should remain evenly moist but not waterlogged to prevent root rot. Watering frequency should increase as the plant develops more leaves and begins to actively take up water. Calla lilies benefit from bright, indirect light or partial shade, receiving at least six hours of sunlight daily for foliage development. Applying a balanced liquid fertilizer every two to four weeks during this growing season supports healthy leaf and root development, though too much nitrogen can lead to excessive foliage at the expense of flowers.
Flowering Stage
As the calla lily matures, it transitions into its flowering stage, typically producing blooms 8 to 16 weeks after planting. This phase is marked by the emergence of tall, sturdy flower stalks, known as scapes, that rise above the foliage. Each stalk culminates in the distinctive calla lily bloom, which consists of a colorful, funnel-shaped spathe enveloping a central finger-like structure called the spadix. The spathe slowly unfurls and can display a wide array of colors, from classic white to vibrant yellows, oranges, pinks, and deep maroons.
Individual blooms can last for several weeks, and the overall flowering period for a plant can extend for six to twelve weeks. During this time, the plant’s water requirements increase, necessitating consistent soil moisture to support the blooms. Continued fertilization with a balanced liquid feed, or one slightly higher in phosphorus, every two to three weeks sustains flower production. Removing spent flowers by cutting the stem at the base (deadheading) encourages the plant to direct its energy into producing new blooms rather than setting seeds, prolonging the flowering period.
Post-Flowering and Dormancy
After blooms fade, the calla lily naturally enters its post-flowering and dormancy phase, a resting period for the plant’s health and future flowering cycles. During this transition, the foliage gradually begins to yellow and decline, signaling that the plant is drawing nutrients and energy back into its underground rhizome for storage. Allow the leaves to yellow naturally rather than cutting them back immediately, as this process ensures maximum energy transfer to the rhizome.
As the foliage dies back, gradually reduce watering and eventually cease it entirely. Overwatering during this time can lead to rhizome rot. For calla lilies grown in USDA hardiness zones 8 and warmer, the rhizomes can remain in the ground over winter with a protective layer of mulch.
In colder climates (zones 7 and below), the rhizomes are not winter-hardy and should be dug up after the first light frost has killed the foliage. After digging, clean the rhizomes, allow them to cure in a warm, dry place for several days to a week, and then store them in a cool, dark, and dry location (around 45-55°F or 7-13°C) until the next spring. This dormant period allows the plant to rejuvenate and prepare for another season of growth and blooms.