Q.Do Canna Bulbs Get Too Old?
I have dug up and replanted my canna bulbs for at least 7 years Not flowering this year
Certified GKH Gardening Expert
The Cannas should not lose vigor due to age. Likely, a soil test will be necessary to see what needs to be added back. Testing pH can help rule out the possibility of a pH swing.
Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
https://www.gardeningknowhow.com/ornamental/bulbs/canna/canna-lily-care.htm