As research shows, over several years miracle grow wipes out your soil and the plants have a drug like addiction to it. Your soil is filled with salts so what I would do is, on a morning of a warm day, run your hose slowly into your pot for 3-5 minutes to flush out the salts. Then let your plants dry for a week. If it rains put a plastic bag from the stem down so water runs off and not into the pot ( you can use a plastic paper plate that you cut a hole for the stem and a slit to the side so you clip it on upside down on top of the pot with the stem coming out the hole.) On the 7th evening water with about a gallon and then on the next morning give a half dose of fertilizer (read label) if it is mixed with water (water soluable) or a full dose if granular. Wait the recommended max time (if it says every 7-14 days wait 14) and repeat with a full dose. Do not water daily. Plumerias like to dry out a bit which encourages flowers. When they are constantly wet in the roots they have problems more often. They are from areas which have tropical rains then dry periods so they do best when that is duplicated in your garden. Misting is fine but keep the soil from being constantly wet. Bill

Valarina, how long have they been in the pots they are now in? Your post makes it sound like you have repotted them several times recently. They may just need tome to adjust to their new surroundings. Generally, you will know they need repotting when you start to see the roots coming out of the drainage holes. Also, what type of pots do you have them in. Plumerias do bettter in plastic pots than in clay pots.

Plumerias are heavy feeders. Unless you are really going overboard with the fertilizer, that should not be the problem.

One other thing you may want to consider. Were they in their old pots for a long time? Sometimes when they are rootbound, their roots will grow circular and they will continue to do so even in a larger pot. It is like an old habit that is hard to break. Before repotting, you should comb the roots downward so they are in a vertical position and can spread out into the new dirt.