Always re-fill holes with the same soil that came out of the hole. Without mixing in anything. Except when growing short term plants with limited root systems such as flowering annual plants and annual vegetables. Those do best in special beds of amended soils.

Improve post-planting conditions by watering diligently and mulching immediately after planting, maintaining a mulch indefinitely. Organic material belongs on top of the bed instead of in it.

Amending or replacement of planting hole back-fill often creates problems with how water enters and exists planting holes, resulting in impeded or retarded plant establishment rather than enhancing it. Where existing soils are thought unsuitable for kinds of plants being planted excavate and replace entire bed sized areas with suitable soil. (Actual soil, consisting mostly of sand, silt and clay, and not a prepared mix that is very high in organic material, like one might use for filling flower pots). Or dump it on top of the existing soil, to create berms, mounds or contained raised beds, plant in those without blending the two soils together.

great info ! thanks

https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub

i swear i asked and provided this for you ...

look for section on proper planting time ... and there arent many places where august is proper ... why cant you hold them until fall.. when night temps fall significantly l..

then for section on native soil ...

then proper watering ...

ken