Can orange rust fungus attack cannas? I suddenly have leaves dying and something that looks very much like it on the leaves and
stems. This has been a gorgeous healthy productive plant about 5 feet tall with several clusters and tons of blossoms. Can it be saved? Orange spots in photo are on front and back of leaves and on the stems ... only on the older portions of the plants. Suggestions? I am already on your weekly mailing list and love it. Thank you!
Certified GKH Gardening Expert
Every plant can be affected by some kind of rust. The treatment can be pretty simple, but the best method will be prevention. This usually occurs when the soil remains wet for too long. If you can help it, make sure to let it dry out pretty well between watering.
You can treat, and prevent with the same method. Apply wettable sulfur and dolomitic lime together, once or twice per year. This will make the soil condition highly unfavorable for infection, but almost perfect for the plant. It will kill any bad things lurking in your soil.
The old growth will not recover, and the spots will not go away, but after treatment they will not spread or be on new growth.
This article will help: https://www.gardeningknowhow.com/ornamental/bulbs/canna/canna-lily-care.htm