I second the motion for subsoiling to break up plow pan, etc.
Many vineyard owners subsoil before planting. I would subsoil then cover crop if you have the time (ask local ag extension agent), then plant, top-dress compost and chips.
Also suggest buying two recent books on pawpaw culture by Michael Judd and Blake Cothron.
According to the University of Kentucky pawpaw prefers fertile, moist soil that is slightly acidic, and will sometimes tolerate wet soil. But like most fruit trees they prefer well drained soil. Your soil has good surface drainage and probably slow internal drainage. Will that work, no one can say.
If I were looking for an orchard location and saw soil that looks like yours Iād turn and run. The color and the slick appearance of the sidewalls isnāt pretty. But who knows it might grow great pawpaw.
Your reading my mind thats why i said do a 5 tree test crop then he knows what he has. With pawpaw there is a good chance they will be fine. Ive seen them live after being underwater for a long time. Itās all about the pawpaws genetics. Any other tree im not so sure would do well there. Pawpaw in my experience like damp ground that will kill most fruit trees.
Iād advise just planting them and get on with it. If the baby plants are about twenty months of age, they should make it. Get a pH test doneā¦for Charlotte has some areas way lower than 6 or 7ā¦and 6 to 7.5 is probably going to be necessaryā¦about 6.5 ideal.
Not sure the source of your gray soilā¦from Union County, NC to the Tennessee border, Iāve not seen that color soil though.
I planted 3 peach trees I got from lowes, there 10 years ago and they did great for a few years, but then got brown rot so the fruit is ruined every year, but the trees themselves seem healthy. That was before I imported the clay loam from the lake a mile down the street when they made a new boat dock and added 300 yards of wood chips. Couple wild peach trees sprouted up after wards.
Iām sure paw paw trees will grow there. Also know that I only have once chance to amend the soil before the trees are planted. Afterwards itās too hard to amend the soil easily. Yes I could amend one by one, but much faster to do with 40ā long semi trailers of mulch, etc.
for the sake of science Iāll probably amend some and not others and see how they do several years latter.
grey soil is from lake wylie, sc, when the police department mile down the road, dredged up some land to make a new boat dock. clay under neath it is reddish.
Post hole digger or shovel and just do it. They have taproots that are going deeper than anything you can amend. Your top dressing will take care of feeder roots. Composted manure and wood chip is great. They grow wild here and where they really like is on the edge of the river. So your river import may feel more like home. For the most part pawpaw seedlings are pretty cheap and I would plant them in pairs to choose the better later. Or should one die.
We use a post hole digger, but if I had the space, I would totally try the Miyawaki method for FAST growth. Imagine getting fruit in 3-4 years instead of 6-7. I think itās totally possible with the Miyawaki method. Iām racking my brain trying to think of a space to try this in here on my property.
Red clay indicates good drainage. Red indicates that the iron is oxidized. Your site will probably be fine for what you want.
Plus you said youāre on a slope. So, plant awayā¦and add some lime if a soil test suggests it.
I have put a shovel in the ground more than once in York and Lancaster counties. Also Union, Mecklenburg, Gaston and Cleveland counties.
But, itās too hot there in the summertime. 
Most of your red clay still will perc --not an impervious subsoil. Good luck with your project
Just get a post hole digger and plant them. Mulch heavily for a few years. If you get past the first 2 season then pawpaws grow themselves.
First 2 season are tough. They need shade and water but not too much water.
No need to go crazy
True Iāve seen them growing in the middle of creeks where their is sometimes standing water and most certainly always moist.
Disclaimer Iāve never grown and Orchard on a larger scale but this method has worked for my five trees with similar soil conditions. Since you have 6 to 12 inches of mulch I would pull back the mulch and make mounded rows or individual planting spots, cover back up with mulch. If you plant at ground level by the time the mulch turns to dirt your trees will be too deep. I would also recommend using urea fertilizer or something high nitrogen ( They really didnāt grow until I hit them with urea) Iāve read that mulch can rob nitrogen at first before it breaks down. Good luck and keep us posted.
Is your pawpaw orchard a hobby? or are u going to sell the fruit? Curious.
How will 90 trees pollinate? Will you need to irrigate?
I am new to pawpaws myself and only plan on planting 12 or so. The pollination is wonkyā¦ There have been suggestions to hang roadkill in trees to attract the flies and beetles.
Pawpaw trees will need regular watering during the growing season. Supple-mental fertilizer should be added annually in late win-
ter or early spring.
Flies and beetles are thought to be the pollinators;
however, since they are neither efficient nor depend-
able, hand pollination can be helpful to ensure plenti-
ful fruit set for small home plantings
Since you are getting one year old seedlings and plan to grow them in pots (in shade or partial shade I presume)ā¦
by fall '23 or spring '24 you just need to dig (mattock, shovel?) big enough hole to bury a lump of dirt the size of your pots.
No need to over think it.
I might sell fruit. I have a well about 100ā away I will use to irrigate. Iāll get several different cultivars and wild seedlings so they should cross pollinate easily I donāt think itās really necessary to put roadkill in a tree because they grow in the wild all over the place here unfortunately the wild trees produce fruit thatās 60% seeds and very small the cultivars produce fruit thatās 3% seed and very big
Yes I have just stuck fruit trees in the ground before Iām just wondering if I can shave a year or two or three and have them grow stronger by doing something to the soil ahead of time. It might actually make economical sense to spend a little more money upfront because one could easily make their money back with a year or two of fruit production
I see youāve already done a bunchā¦the dredged soil from the lake, the chipsā¦
so I understand your point. Perhaps try to get a little āextraā growth the one year theyāll spend in pots might be the next best place to push them a little.
I am in Zone 7B (North Alabama) and have a very similar situation. I cleared half an acre that is at a similar slope. Cleared all the trees out and put down 12 inches of wood chips. When I started, the clay level was around 6 inches below before the clay horizon starts. What was once hard soil, where I could drive my small tractor (24 hp), I now have to be more careful about getting stuck.
I also have a situation, where some of the holes I dug, water would seep in from the bottom of the hole (called Capillary Action). Had to put gravel in the hole and build a small mound on top. Now the tree roots are into the permanently damp clay and doing well.
After a year of wood chips and heavy rain some small areas chips floated away. In those areas I am now adding white clover. I will over seed and repeat after each heavy rain so I get clover a good start.
Water seeps into the hole because there is a high water table not from capillary action. Putting gravel in the hole doesnāt help. Building a mound does help. A mound gets the tree farther above the water table.
Water seeping into a hole is the slowest drainage test one could have. Water doesnāt drain out of a dug hole, it seeps in. The final water level in the hole is the level of the water table. Often a high water table is a seasonal thing. The water table rises in the wet season and falls in the dry season or when plants are using a lot of water.
I had a seasonal creek on my property in California. The creek actually flowed all year around. But during the summer the water level fell below the creek bed. In fall well before the first rains the creek began to flow again. As the weather cooled water use by vegetation along the creek dropped low enough that the water table rose above the creek bed.