The plants are in a concrete planter with moist soil and that I fill with water each day. But the stems are not very strong even though they have grown to over 6 ft. they are very fraagile.
How Do I Cure Rust Spots on Papyrus Stems?
Certified GKH Gardening Expert
Rust fungus is a known issue on Papyrus.
Here are some links to help you.