pH has been the key problem every time I encounter shrubs growing poorly. Sadly, most shrubs want a pH below 6.5. Not easy when most of the land being developed is on coral or has coral used as the base course. Applying 1 lb of citric acid monthly is a fast acting treatment while I am waiting for sulfur to work.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738