Q.Plumeria question
My Plumeria has black spots on the bottom leaves. Top leaves look good. What do I do?
Certified GKH Gardening Expert
This is a common issue caused by overwatering. Usually, making the soil more acidic with Wettable Sulfur will take care of the issue, both, in killing off the culprit responsible, and bringing the soil pH back down to where it needs to be. They tend to like acidic soil.
If you water by hand, or provide any extra water at all outside of natural rain, then make sure you only do this when the top 2 or 3 inches of soil is completely dry before watering again.
This article will give you more information on the care requirements of the plant: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/growing-plumeria.htm