When to fertilize
Knowing when to fertilize is as important as using the right fertilizer. If you don’t apply the fertilizer at a time when the plumeria can use it, there’s no point in fertilizing. Most plumerias bloom great if fed with a balanced granular fertilizer in early spring. Avoid fertilizing before the spring showers or you will be throwing your money away since the nutrients will simply leach out of the soil. Using a slow release is best.
Annuals like to be fed an additional three to four times during the growing season with a high-phosphorus, water-soluble fertilizer, while Plumeria benefits from a balanced granular application in early spring.
Just remember, these guidelines on feeding are just that—guidelines. Read the package directions before scattering both food and caution to the wind.