There has been a fair amount of confusion in the literature about whether or not to add amendments to the planting hole for a tree or shrub.
WE KNOW THIS. WE ADD NO FERTILIZER OF ANY KIND TO THE PLANTING HOLE. THE TREE OR SHRUB NEWLY PLANTED IS NOT FERTILIZED FOR A YEAR!
On the other hand, we have learned that there a number of OPTIONAL amendments that can be helpful in reducing stress in the tree or shrub and assisting the plant in becoming established in its new location. You can add one, two, or all of these amendments in small amounts and be doing good for the new transplant.
A cup or two of quality compost will be helpful to the plant and to the soil creatures living in the plant's area.
Mycorrhiza are root fungi that attach themselves to the roots of a tree or shrub and help those roots retrieve water and nutrients for the plant. A tablespoon of powdered product should be more than enough.
Go to Yardener's Tool Shed for Mycorrhizae products; click here
Adding Beneficial Soil Microbes
Soil microbes are now available in many forms. Usually they come in a powder. A tablespoon should be plenty.
Go to Yardener's Tool Shed for microbe products, click here
Adding Water Absorbing Polymers
Water absorbing polymers are very helpful in getting the new transplant through the next year when water might no always be available. To see some polymer products go to our Yardener's Tool Shed; click here
BioChar is a relatively new product. a cup of granular biochar should be beneficial
Adding seaweed or kelp powder or liquid
Avoid any seaweed or kelp product containing fertilizer. Here you want the pure seaweed or kelp liquid or powder. A quarter cup should be very good for the plant