“This year, I didn’t get many blooms on my cannas. Any ideas?” Question from Gloria of Morgan Hill, California
Answer: I’m sorry to hear that your cannas did not bloom well. Let me cover everything that they need to grow and flower to their fullest, followed up by some danger areas, and you can troubleshoot from there.
What Cannas Need to Grow Well
Cannas (Canna species and hybrids, Zones 8-11) are lush, tropical to subtropical perennials adapted to full to partial sun, and rich moist to average soils. Providing a boost of continuous-release fertilizer formulated for flowers always encourages good blooming. They originate from warm regions of the Americas where climates are humid and rainy. When growing conditions are ideal, they will flower with no trouble. If they are not hardy where you live, dig their rhizomes in fall and store them in a cool, dark place through winter.
Conditions that Discourage Canna Flowering
Here are several suboptimal growing conditions that will discourage blooming cannas: too little water, too little light, low humidity, and too little fertilizer.
There are also several viral diseases that will discourage growth and flowering in cannas. These include the Canna yellow streak virus (CaYSV) and Canna yellow mottle virus (CaYMV), among others. Plants with these diseases show abnormal leaves with browning or yellowing streaks of mottled patterns. If your canna leaves exhibit either, dispose of the plants immediately and replace them with certified virus-free stock (specialty growers are usually the most reliable source). Be sure not to reuse the potting soil, if your plants are in containers.
I hope that this helps!
Black Gold Horticulturist