Released by UF/IFAS …
by Celeste White
Are you asking “Why do the shrubs look like this?” The answer might be that the shrubs are planted too deep which can eventually kill them. Roots are deprived of oxygen when smothered. The above-ground symptoms are similar to root rot — chlorotic foliage, lack of growth, thinning of the canopy, and a general slow decline. Improper planting can be the cause. No soil should be placed on top of the root ball. Excessive mulch can also cause a plant’s roots to be too deep. Always pull back and/or remove excess mulch from the base of the plant.
It is important when you are planting trees and shrubs to find the topmost roots before planting. Plants in containers can have too much soil over the root ball when they arrive from 
the nursery. Once the top-most roots are located, they should be planted an inch or two higher than the existing soil line.
Another way to prevent deep planting is to dig the hole no deeper than the root ball. When the soil is loosened up under the root ball, the plant can settle after planting. After planting, UF/IFAS researchers recommend that no soil or mulch be placed over the root ball.
Replanting at the correct depth may allow the plant to recover if the problem is caught early but planting it right the first time is best!
Steps to planting a shrub can be found here: