How to Prune Canna Lilies
Rarely content with a limited palette, flamboyant cannas (Canna spp.) bloom in a multitude of yellows, oranges, pinks and reds. Gilding the lilies are enormous, paddle-shaped leaves, many with intricate, colorful variegated stripes.
Whether you grow them as perennials in U.S. Department of Agriculture plant hardiness zones 8 through 12, or as annuals lifted for overwintering indoors elsewhere, properly pruned cannas may bloom for months.
Deadheading means pruning off dying flowers before they set seed, so the plant channels its energy and nutrients into making new blooms. Because each canna stalk simultaneously holds open and developing flower shoots, this is an ongoing process. Begin deadheading when the top, or terminal, shoot of flowers on a stalk has withered.
Snip the withered flowers off the stems with a clean, sharp pruning shears.
Disinfect the pruning shear blades with a clean towel or rag moistened in rubbing alcohol after each cut you make.
Place the pruned material in a plastic trash bag for disposal or add it to your compost bin.
Check the stems for secondary, partially open flower shoots emerging from nodes, or raised areas, just below the cuts. Monitor and deadhead them as soon as they finish blooming.
Wait for the next flower shoots to open, and repeat the process until the stems stop producing shoots. Then cut the entire stalk, leaves included, to 1 or 2 inches above the soil.
- Removing the pruned material promptly keeps the garden bed tidy and reduces the risk of fungal disease.
- Cutting the finished stalks and leaves back allows more more light and nutrients to reach the remaining ones and stimulate their flower production..
Because even non-flowering cannas draw attention for their leaves, their dead or insect- and disease-damaged leaves are especially noticeable. Prune them back to their stalks or -- if an entire stalk is damaged, back to the ground -- any time. Remember to disinfect the pruning shears between cuts.
Cut frost-blackened foliage back to ground before lifting the rhizomes for winter storage.
Passionate for travel and the well-written word, Judy Wolfe is a professional writer with a Bachelor of Arts in English literature from Cal Poly Pomona and a certificate in advanced floral design. Her thousands of published articles cover topics from travel and gardening to pet care and technology.