The Calla Lily (Zantedeschia) is an elegant, rhizomatous perennial. These plants are seasonal bloomers, typically completing one primary flowering cycle per year. However, with precise care and favorable growing conditions, especially for hybrid varieties, it is possible to encourage the plant to produce a second flush of blooms within a single growing season. This potential for reblooming moves the plant to a continuous source of color.
The Typical Blooming Period
The Zantedeschia generally begins its main flowering display in late spring and continues through mid-summer, depending on the climate and planting time. After the rhizome is planted, it typically takes about 13 to 16 weeks before the first flower stalks emerge from the foliage. This main period of flowering usually lasts between 6 and 12 weeks.
An individual Calla Lily flower is durable and can remain on the plant for several weeks. To maximize the display, pull spent flower heads off at the base of the stalk, a process known as deadheading. This redirects the plant’s energy away from seed production and toward new growth and potential subsequent blooms.
Environmental Factors That Influence Frequency
A Calla Lily’s ability to bloom more than once in a season depends on optimizing its environment and nutrient availability. The plant requires significant light to store the energy needed for repeated flower production. Aim for a location that receives full sun to partial shade. In regions with intense afternoon heat, providing light shade during the hottest part of the day can prevent leaf scorch while still supporting bud development.
Consistent soil moisture is necessary for reblooming. The soil must remain consistently moist but never waterlogged, which can quickly lead to rhizome rot.
An imbalance of nutrients can inhibit flower formation. High-nitrogen fertilizers should be avoided, as they promote lush, leafy growth at the expense of blooms. Instead, use a balanced, water-soluble fertilizer or one formulated with a higher phosphorus ratio once or twice a month during the active growing season. Phosphorus plays a direct role in flower and root development, encouraging the plant to initiate new buds.
Preparing the Plant for Dormancy and Next Season’s Bloom
To ensure a reliable and abundant bloom in the following year, the plant must undergo a mandatory rest period, or dormancy, which must last for at least two to three months. Once the plant has finished flowering in the late summer or early fall, gradually stop watering the plant, allowing the soil to dry out completely over a period of several weeks.
The remaining foliage will naturally begin to yellow and wither. It is important to allow this process to happen, as the leaves are still transferring vital energy and stored nutrients back into the underground rhizome. Once the foliage has turned entirely brown and withered, it can be cut back to just an inch or two above the soil line.
In colder climates, where the ground freezes, the rhizomes must be lifted and stored indoors before the first hard frost. After carefully digging up the rhizomes, they should be allowed to cure for two to three days in a warm, dry location with temperatures around 60 to 70 degrees Fahrenheit. Following the curing period, store the dormant rhizomes in a container layered with peat moss or sawdust in a cool, dark location, ideally maintaining a temperature around 50 degrees Fahrenheit, until spring planting.