brown spots on leaf underside
My Zee Zee plants do well but recently I've notice brown spots developing along the edge of a leaf. These spots are increasing in size and darken almost to a black color. I can not see any pests or mildew, etc. A spot develops on the underside of a leaf and a few days later there is a hole in the leaf.
Certified GKH Gardening Expert
This could be due to overwatering; the biggest issue with ZZ plants.
This article will refresh you on the care requirements.