Gardenia Help Question

End of last summer my neighbor let me have a couple buckets full of the cutlings from his 6' tall hedge of gardenias.
I rooted them in water vases and babied them all winter and planted about 25 into the ground earlier this spring.
They are doing awesome, even flowered later in the spring.
Now I have 5 plants (consecutively in the row) that appear to be losing the battle to the heat.
I gave them all some osmocote plus when I first planted, nothing but water since.

Im wondering if the "dead" ones will revive? weird that there are healthy ones all around, but those 5 in a row decided to decline.

any thoughts or help would be appreciated.