The Calla Lily (Zantedeschia) is typically grown in garden soil, but its natural habitat provides a significant clue to an alternative cultivation method. Certain species naturally thrive in environments far wetter than a standard garden bed. This adaptability raises the question of whether they can be successfully grown in a purely water-based system for a unique indoor display. The answer lies in understanding the specific species and replicating the conditions of its native marshy home.
The Feasibility of Water Cultivation
Growing Calla Lilies in water is possible, but success hinges on selecting the right species. The plant most suited for sustained water culture is the common white Calla Lily, Zantedeschia aethiopica, often known as the Arum Lily. This species is native to marshy areas in Southern Africa, establishing it as a true bog plant that can tolerate perpetually wet or shallowly submerged conditions.
The rhizomes of Z. aethiopica are adapted to absorb water and nutrients from saturated soil, mimicking a pond margin. This allows it to grow in a container of water long-term, provided the conditions are managed correctly. In contrast, vibrant, colored Calla Lilies are hybrids derived from other Zantedeschia species that require well-drained soil to prevent rot. Attempting to grow these hybrids in water will lead to failure, as they lack the natural tolerance for constant saturation.
This process is distinct from simply placing a cut flower in a vase. It involves encouraging a dormant rhizome to develop a robust root system and foliage while suspended in a nutrient-rich water solution. This method relies on the plant’s ability to function as a marginal aquatic species in a controlled indoor setting. The key is to manage the water level and oxygenation to prevent rhizome suffocation and decay.
Preparing the Hydroponic Setup
Establishing a Calla Lily requires careful preparation of the rhizome and the chosen container. Select a healthy, firm rhizome of Zantedeschia aethiopica that shows no signs of mold, ensuring it has at least one visible growing point, or “eye.” The ideal container is a clear glass vase, which allows for easy monitoring of the water level, root development, and potential algae growth.
The suspension of the rhizome is the most important step for preventing rot. The bulk of the rhizome must not be fully submerged in the water. Only the bottom third of the rhizome and the newly developing roots should be in contact with the liquid, allowing the upper portion and the plant’s crown to remain exposed to air.
To achieve this partial submersion and anchor the plant securely, support materials are necessary. Use clean pebbles, glass marbles, or a layer of gravel to create a stable base for the rhizome. Arrange these materials around the rhizome, holding it firmly in place so that the crown sits just above the intended water line. Maintaining this precise water level is crucial, as too much submersion quickly leads to oxygen deprivation and rhizome decay.
Nutrient Requirements and Ongoing Care
While the Calla Lily can initially sprout, plain water does not contain the necessary elements for sustained growth and flowering. The plant requires a continuous supply of macro- and micronutrients. This is achieved by adding a balanced, water-soluble liquid fertilizer to the water reservoir.
The fertilizer concentration must be significantly diluted, often to a quarter or half of the strength recommended for soil applications, to prevent chemical burn to the roots. A regular feeding schedule, typically every two weeks during the active growing season, will ensure the plant receives essential elements like nitrogen for foliage and phosphorus for flower development.
Ongoing care focuses on maintaining the quality of the water environment. The water must be changed weekly to replenish oxygen levels and prevent the buildup of stagnant water. When changing the water, gently rinse the roots and the container to remove any slimy residue or accumulated debris.
The water-cultured Calla Lily needs bright, indirect sunlight for a minimum of four to six hours per day. Consistent room temperature, ideally between 60°F and 75°F, encourages steady development. Regular inspection of the rhizome for any softening or discoloration is a necessary precaution, as these are early signs of rot that indicate the water level or oxygenation needs immediate adjustment.