The Purpose of Calla Lily Dormancy
Calla lilies, originating from South Africa, are tender perennial plants that grow from rhizomes and naturally enter a period of dormancy. This resting phase serves as a survival mechanism, triggered by environmental cues such as cooler temperatures, reduced light, or decreased water availability. For outdoor plants, dormancy typically begins in late fall or early winter as temperatures drop. Potted or indoor calla lilies usually enter dormancy after their blooming cycle concludes.
The primary benefit of dormancy is energy conservation and rejuvenation for the plant. During this period, the calla lily can recover from the energy expenditure of blooming and foliage growth. A proper dormancy period, typically lasting at least two to three months, contributes to more vigorous growth and a more abundant display of flowers.
Preparing for Dormancy
As a calla lily prepares for dormancy, the plant’s leaves will naturally begin to yellow and eventually die back, indicating that it is drawing nutrients and energy from the foliage to store in its rhizomes. During this transition, gradually reduce watering, allowing the soil to dry out more completely between applications. This gradual reduction helps signal to the plant that it is time to slow down its metabolic processes.
Allowing the foliage to yellow and die back naturally is beneficial because the plant is actively reabsorbing valuable nutrients from the leaves. Once the foliage has completely withered and turned brown, it can be cut back to about one to two inches above the soil level. This tidies the plant and signals the completion of its preparation for the dormant period.
Caring for Calla Lilies During Dormancy
Once calla lilies have entered their dormant phase, their care shifts significantly to focus on the rhizomes. For plants grown outdoors in colder climates (below USDA Zones 8-10), the rhizomes should be dug up before the first hard frost. After carefully lifting them from the soil, it is important to gently clean off any excess dirt. Inspect each rhizome for any signs of disease, damage, or soft spots, as unhealthy rhizomes may rot during storage.
Healthy rhizomes should be allowed to cure in a warm, dry place, typically between 65 to 75 degrees Fahrenheit, for about three days. Following this curing period, store the rhizomes in a cool, dark, and well-ventilated area where temperatures remain consistently between 50 to 60 degrees Fahrenheit. Packing them in a medium such as slightly moist peat moss or sawdust provides insulation and helps maintain appropriate humidity, preventing excessive drying while avoiding moisture accumulation that could lead to rot. Regularly checking the stored rhizomes ensures they remain healthy throughout the dormant period.
Waking Calla Lilies From Dormancy
The process of reawakening calla lilies from dormancy typically begins in late winter or early spring. Before replanting, it is beneficial to inspect the stored rhizomes once more, ensuring they are firm and free from any signs of rot or mold. Any shriveled or soft sections should be discarded. This inspection helps ensure healthy growth once replanted.
Plant the rhizomes in fresh potting mix or in the garden, orienting them with the growing tips facing upwards, about 1-2 inches deep. Initially, water sparingly to prevent rot, providing just enough moisture to lightly dampen the soil. As new shoots begin to emerge, gradually increase watering, ensuring the soil remains moist but not waterlogged. Placing the pots in a location with bright, indirect light and warmth will encourage sprouting and the resumption of active growth.
Common Dormancy Challenges
One common issue is a calla lily not entering dormancy, which can occur if the plant receives continuous warmth, excessive water, or is grown indoors without a simulated rest period. While not strictly necessary for survival, a proper dormancy period is highly recommended for promoting vigorous future blooms. If a plant remains actively growing, simulating dormancy by withholding water and moving it to a cool, dark location for a couple of months can encourage it to rest.
Rhizomes can rot during dormancy, often due to excessive moisture, poor ventilation during storage, or pre-existing fungal diseases. To prevent this, ensure proper curing and storage methods are followed. If a calla lily fails to re-sprout after dormancy, it may indicate that the rhizome has rotted or dried out completely, or that the dormancy period was insufficient. Checking rhizome health and ensuring proper reintroduction to light, warmth, and gradual watering can help address this.