Canna lilies are tropical plants, prized for their vibrant flowers and striking foliage, that grow from underground rhizomes. Deadheading is the process of removing spent or faded flowers to encourage a better and longer display of blooms. This simple maintenance task influences the plant’s natural growth cycle, maximizing its ornamental value throughout the season.
Why Deadheading is Beneficial
Deadheading redirects the plant’s energy. When a canna lily flower fades, the plant naturally attempts to produce seeds for the next generation. This reproductive process demands significant energy reserves, drawing resources away from the rhizome and new growth. Removing spent flowers before seed production signals that reproduction has not succeeded, compelling the plant to produce more flowers instead.
This redirection promotes repeat blooming, helping the plant produce new flower spikes continuously throughout the summer and fall. The conserved energy is focused on developing new shoots, strengthening the underground rhizomes, and supporting the colorful leaves. Deadheading also provides an aesthetic benefit by removing unattractive, wilting flowers and developing seed pods. Keeping the plant tidy reduces moisture collection, which minimizes the risk of fungal disease or rot.
The Proper Deadheading Technique
Deadheading canna lilies involves two cutting strategies based on the flower spike’s development. Initially, while the stalk is actively producing new buds higher up, only remove the individual spent blossoms. Use a clean, sharp tool to snip off the faded flower just above where it joins the main stalk, taking care not to damage developing buds. Since canna lilies produce multiple flowers on one stalk, preserving the forming buds is important.
Once all flowers on a single stalk have faded and no new buds are visible, remove the entire spent stalk. Trace the stalk down to the nearest healthy leaf or to the base of the plant. Make a clean cut just above a leaf node or where the stalk emerges from the main stem. Removing the entire stalk improves appearance and directs energy toward producing new flower stalks from the rhizome.
When to Stop Deadheading
The routine removal of spent flowers should be halted if you intend to collect seeds for propagation. Allow faded flowers to remain on the plant so the seed pods can fully develop. Canna lily seed pods are distinctive, appearing as round, green, spiky structures where the flower once was. These pods contain hard, black seeds and must be allowed to mature and dry out on the stalk until they begin to split open.
Deadheading must also stop completely toward the end of the growing season as the first frost approaches. When the foliage begins to yellow and die back naturally, the plant is preparing for dormancy. Cut the entire stem and foliage back to about three to six inches above the ground after a light frost occurs. This final cut signals the end of the active growing season, allowing the plant to store maximum energy in its rhizomes for the following year.