Calla lilies (Zantedeschia spp.) are elegant ornamental plants known for their distinctive trumpet-shaped blooms. Regular pruning is a simple yet effective practice that significantly influences the plant’s appearance and long-term health. By removing spent material and preparing the plant for its annual rest period, gardeners ensure the calla lily redirects stored energy efficiently. This process promotes a tidy look and supports the development of strong, healthy rhizomes for the following year’s display.
Pruning Spent Blooms (Deadheading)
The removal of faded flowers, known as deadheading, is performed during the calla lily’s active growth phase, typically from late spring through summer. This action prevents the plant from expending resources on producing seeds. Spent blooms, which often turn green and begin to roll into a tube shape, should be identified as soon as they start to fade.
To deadhead correctly, trace the spent flower stem down to the base of the plant, near the soil line. Use sharp, sanitized shears or scissors to make a clean cut as close to the base as possible. Removing the entire stem ensures that no hollow stub remains, which could otherwise collect water and potentially lead to rot.
Trimming Yellowed or Damaged Foliage
Calla lilies naturally shed their older leaves throughout the growing season. These leaves will begin to yellow or turn brown, signaling that the plant is withdrawing nutrients back into the rhizome. Removing this discolored foliage improves the plant’s overall look and helps prevent the spread of fungal diseases.
To trim these leaves, use clean, sharp cutting tools to sever the leaf stalk near the base of the plant. Only remove leaves that are clearly yellow, brown, or damaged, as healthy green foliage continues to photosynthesize and feed the rhizome. If any foliage shows signs of disease, remove it immediately and sanitize your tools thoroughly afterward to avoid contaminating other plants.
Preparing Calla Lilies for Dormancy
The most significant pruning occurs when the calla lily begins its natural transition into dormancy, typically in late summer or early fall. The plant signals this major cutback when its healthy green foliage starts to yellow and flop over naturally. This change indicates that the plant has finished its seasonal growth and is storing energy in its underground rhizome.
Wait until this natural dieback is well underway or until after the first light frost, ensuring maximum nutrient storage in the rhizome before cutting. The remaining foliage can be cut back sharply to about one to three inches above the soil line. Subsequent steps depend on the local climate and the plant’s hardiness zone.
In warmer regions, specifically USDA Hardiness Zones 8 through 10, calla lily rhizomes are winter-hardy and can be left in the ground. The dormant plant requires a dry rest period, so watering should be stopped, and a layer of protective mulch can be applied over the planting site. This allows the plant to rest and prepare for the next spring’s growth cycle.
For gardeners in colder Zones, typically Zone 7 and below, the rhizomes must be lifted and stored indoors to prevent freezing. After the foliage is cut back, the rhizomes should be carefully dug up, gently brushed clean of soil, and allowed to dry or “cure” in a warm, dry location for several days. This curing process toughens the outer skin, reducing the risk of rot during storage. The dried rhizomes should then be placed in a ventilated container, such as a paper bag or a box filled with slightly dampened peat moss or sawdust. They need to be kept in a cool, dark, and frost-free location, ideally with temperatures maintained between 50 and 60 degrees Fahrenheit.