I read you should alwys add organic matter when plnting new plants, so I mixed some peat moss into each hole. 2 instruction books came with the trees; I read 1 of them 1st. But the 2nd one says "do not add soil amndments such as peat…" WHY is that?? DOES THIS MEAN YOU SHOULD NEVER AMEND SOIL FOR TREES?? Does same go for SHRUBS?? Same go for CONIFERS?? Same for NON-BAREROOT?
Adding compost or other organic matter to heavy clay or sandy soils generally will improve them. However, if just the planting hole is amended with organic matter, roots from the tree may remain in the planting hole rather than spreading to the surrounding soil. in effect, you're creating a container planting in the ground. So, unless you amend a wide area of soil around the planting hole, it's best to simply plant using the native soil.