Welcome to the wonderful, yet mysterious, sometimes straight nerve-wracking world of plumeria.

From the looks of the images you posted of the leaves, you have a sunburn going on there. This might be caused by bringing greenhouse grown plants out into the open (even after a short period of acclimatization) or from humid to dry heat. As long as it is just the leaves, you should be fine and the new emerging leaves should take the conditions much better. Some yellowing on older leaves is fine after a transplant shock, in the heat with dry conditions, but it should not be more than 1-2 at a time.

The branch wrinkling is a little worrisome. This can either be caused by too little water in the soil OR too much water and poor drainage, which suffocate the roots from oxygen which in return makes them rot and unable to take up water, causing a similar response as when there is too little.

Plumeria are tropical plants and they LOVE water, especially when it's warm out there. They just don't like to have wet feet combined with little available oxygen. Your mix sounds good though... does it drain well? If not, you might want to consider some amendments like pine bark, pumice, pea gravel, small amounts of lava rock or more perlite. Do you have enough holes in the bottom of the pots for drainage? If you get the chance to pick up a cheap water meter at HD or Lowe's, it will determine if the problem is too much or too little water. If it's the latter, you just need to water more.

I'd personally steer clear of the bloom booster and use a more balanced approach, along the lines of a 2:1:2 ratio. No plant in the universe needs 5 times the amount of phosphorus compared to nitrogen to bloom or grow roots (biggest benefit of phosphorus-heavy fertilizers). Especially considering that it's not the surplus of available phosphorus that makes a plant bloom but the shortage of nitrogen.

When you say you misted the plant lightly? Does this involve the bloom booster? If so, you eventually have a bit of a chemical/fertilizer burn there too. P is not well taken up by leaves and can cause quite a burn.

Good luck and again, welcome!

Thank you for these answers. I moved the plants into a shadier spot and watered all three plants as the moisture sensor said it was bone dry. I had watered cuttings too much and they got rot last year so I've been too cautious with the watering can. The plants are perking up, yellowing has stopped and we are both happy campers.

great news. I also have some plants that seem to do much better with more shade.

Hello tjbrislin - Just to add to all the wonderful suggestions that you've gotten from above...also heat radiating from the block wall is another factor. Happy growing.

~Kasie