In nearly all landscapes, soil must be loosened if young trees and shrubs are to grow well. Drainage
may also need to be improved. It may be necessary to break up or penetrate hardpan, for example with a
backhoe, to provide greater soil depth. Install drain pipe, drain tile, or a sump if needed to ensure
adequate drainage and good plant growth. Aeration tubes, however, have not been shown to be effective
in increasing soil aeration in the root zone.
Before planting, mark out a planting area that is at least two to three times the diameter of the root
ball. Rototill, shovel, bore, or use an auger to mix the soil within this area to the depth of the plant's
root ball. Mix the soil well. Adding organic matter to the planting hole of trees and large shrubs has
not shown consistent benefits. Amending the entire potential root zone of trees is generally not practical,
and amending soils around established plants will damage roots. Amendments can help before planting certain
shrubs such as camellias or azaleas, which are adapted to well-drained acidic soils and will do poorly
without amendment. If added, organic matter should be well composted and constitute no more that about
25% of the soil volume in the upper 12 inches of the soil. Mix it well into the topsoil. A 2- to 3-inch
layer of mulch also can be added to the surface after planting.