The amount of fertilizer to apply to Plumeria depends on the size and age of the plant, as well as the formulation of the fertilizer. For slow-release granular fertilizers, apply approximately 1 tablespoon per foot of plant height. For liquid fertilizers, follow the manufacturer’s recommended dosage, usually around 1/2 to 1 teaspoon per gallon of water. It’s essential to distribute the fertilizer evenly around the root zone, avoiding direct contact with the plant’s stem. Applying too much fertilizer can lead to nutrient imbalances and damage the plant’s roots.