|i have black spots on some cattelyea leaves|
I am sorry for this delayed reply to your gardening question. The spring rush has brought a deluge of questions and we are working hard to catch up!
Those may be due to a disease but such is unlikely. It could be that you are wetting the foliage which would encourage such problems. Wet the roots but not the leaves to see if this ends up helping. Spraying them should not be necessary. Remove the older affected leaves as new healthy ones appear.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!