Canna lilies offer a vibrant, tropical presence in gardens with their showy flowers and striking foliage. Proper winter preparation helps protect these beautiful plants, allowing them to thrive year after year.
Why Prepare Cannas for Winter
Canna lilies originate from tropical and subtropical regions, making them sensitive to cold temperatures and vulnerable to frost. Their rhizomes, which are underground stems that store energy, can be damaged or destroyed by freezing conditions.
Preparing cannas for winter, which includes cutting back the foliage, helps protect these rhizomes. This process prevents moisture from traveling down the hollow stems into the rhizomes, reducing the risk of rot and fungal diseases during dormancy. This care ensures the plant remains healthy and vigorous, ready to produce abundant blooms in the subsequent growing season.
When to Cut Back Cannas
The optimal time to cut back canna lilies is after the first hard frost. A hard frost causes the plant’s foliage to blacken and die back, signaling that the plant has entered its dormant phase. Waiting for this natural cue is beneficial because it allows the plant to draw energy from its dying leaves back into the rhizomes for storage.
Cutting back too early can interrupt this energy transfer, potentially weakening the rhizomes. In regions with milder winters, cannas might be pruned in late fall or early winter when foliage naturally begins to decline. Observing the plant’s natural response to cooler temperatures is a reliable indicator for timing this task.
Step-by-Step Guide to Cutting Back Cannas
Begin by gathering sharp, clean pruners or loppers and gardening gloves. Sharp tools ensure clean cuts, minimizing damage to the plant and reducing disease transmission. Cleaning your tools with a disinfectant, such as rubbing alcohol, before and after use helps prevent the spread of pathogens.
Cut the canna stalks down to a height of approximately 4 to 6 inches above the ground. This remaining stem acts as a protective barrier for the rhizome below the soil line. Remove any dead, damaged, or yellowing foliage, as this material can harbor pests or diseases.
For cannas grown in containers, cut the foliage back to a few inches above the soil level. The remaining stems allow for easy handling of the rhizomes later. Discard all cut plant material away from the garden to maintain good garden hygiene.
Post-Cutting Care and Storage
After cutting back the foliage, prepare the canna rhizomes for winter storage, especially in colder climates where ground freezing is common. Dig up the entire clump of rhizomes by inserting a shovel or garden fork about 6 inches away from the plant base to avoid damage. Lift the rhizomes from the soil, shaking off any excess dirt.
Allow the rhizomes to air dry in a well-ventilated area for a few days to a week, at temperatures between 70 to 80 degrees Fahrenheit. This curing process helps to toughen the outer skin, making the rhizomes less susceptible to rot during storage. After drying, remove any remaining foliage or fine roots, and inspect the rhizomes for any signs of disease, damage, or soft spots, discarding affected portions.
Store the cleaned and dried rhizomes in a cool, dark, and dry location where temperatures remain consistently between 40 and 50 degrees Fahrenheit, such as a basement or cellar. Good air circulation is important to prevent moisture buildup. Avoid storing them in areas prone to freezing temperatures, like an unheated garage or attic.
Place the rhizomes in a cardboard box, paper bag, or mesh bag, layered with a dry, breathable material such as peat moss, vermiculite, or shredded newspaper. This material absorbs residual moisture and provides insulation. Ensure rhizomes do not touch to prevent rot spread. Label the container for easy identification next spring. Periodically check stored rhizomes throughout winter for desiccation or spoilage, adjusting conditions or discarding as needed.