Canna lilies are tropical perennials known for their vibrant foliage and showy flowers. As these plants mature, their robust underground structures, called rhizomes, rapidly multiply, leading to overcrowding within a few years. Transplanting is necessary to divide these crowded rhizomes, maintain plant health, or move the clump to a new location. Successfully relocating canna lilies depends on performing the operation when the plant is least active, minimizing physiological stress.
Optimal Timing Based on Climate
The ideal moment for transplanting canna lilies varies significantly depending on the regional climate. For gardeners in warmer USDA Hardiness Zones (8-11) where cannas remain in the ground year-round, the best time to move them is in the late fall. This timing occurs after the flowering season has ended and the foliage has begun to die back naturally, signaling that the plant is entering a semi-dormant state.
In colder zones (Zone 7 and below), where cannas must be lifted and stored indoors to survive winter, the optimal time for replanting is early spring. The rhizomes should be put back into the ground only after the last danger of frost has passed and the soil temperature has reached a consistent 60°F or warmer.
Transplanting during this period of dormancy reduces the demand on the root system to support active foliage. Attempting to move a fully leafed-out, actively growing plant in the middle of summer results in substantial shock and a higher risk of failure. Spring replanting gives the plant an entire growing season to establish itself.
Preparing and Extracting the Rhizomes
Before digging, cut back the existing foliage severely to reduce water loss and provide clear access to the root mass. Trim stems down to stubs of about six inches above the soil line, or closer to one inch if the plant is fully dormant. Use a garden fork or spade to loosen the soil in a wide circle, approximately one foot away from the center of the stem, to avoid slicing into the rhizome clump.
Gently lever the entire rhizome mass out of the ground once the soil is loosened, keeping the clump intact as much as possible. Shake or brush away excess soil to expose the individual rhizomes and their growth points, known as “eyes.” The mass should then be divided using a sharp, sterilized knife or snapped apart at natural constrictions. Each division must contain at least two to three healthy eyes and some fibrous roots to ensure successful regrowth.
Inspect the cleaned rhizomes for any signs of rot or damage, cutting away soft or discolored sections. Consider dipping the healthy divisions in a mild fungicide or a 1:10 bleach-to-water solution before replanting.
The Replanting Process
Select a new location that offers full sun exposure, ideally receiving at least six hours of direct sunlight daily, to promote robust growth and flowering. The soil at the new site must be well-draining, as cannas thrive in consistently moist but never waterlogged conditions, which can lead to rhizome rot. Prepare the planting hole by digging it twice as wide as the rhizome clump and deep enough to accommodate the root system.
Before placing the rhizomes, enrich the bottom of the hole by mixing in well-aged compost or other organic matter to improve nutrient content and drainage. Position the rhizomes horizontally in the hole, with the eyes facing upward, and cover them with about two to three inches of soil. Gently firm the soil around the rhizomes to eliminate air pockets and ensure good soil-to-root contact. Finally, water the newly planted area thoroughly to help the surrounding soil settle and begin hydration.
Post-Transplant Care
Immediately following replanting, consistent and deep watering is essential for reducing transplant shock and encouraging root establishment. Keep the soil continuously moist, especially during the first few weeks, but never allow it to become saturated or soggy. Applying a layer of organic mulch, such as shredded bark or straw, around the base of the plant helps regulate soil temperature and retain moisture.
Monitor the transplanted cannas closely for signs of stress, such as wilting or yellowing foliage. While some wilting is normal, persistent symptoms may indicate insufficient water or poor drainage. Withhold nutritional support until the plant shows clear signs of active new growth, usually several weeks after the move. Once new shoots are underway, apply a balanced, slow-release fertilizer, as cannas are heavy feeders that benefit from extra nutrients.