First, how big of a tree did you have removed?

Weeping cherry...I bet 8ft tall and 6 wide at death? And you only had to chainsaw it at ground level and no stump to speak of.

I would use google and figure out if your choices for replacement are liable to catch the same disease or are unlikely to. Different plants, different diseases ya know.

If they are unlikely to catch it then go for it.

it concerns me more.. that you are thinking of planting in july/august.. [hopefully you are thinking a fall planting]

rather than what you might put in a hole...

dig hole twice as big as pot .... remove all old roots ... insert plant.. refill with what you dug out... move on with life.. yours and the plant ...

inconsequential.. IMHO ...

if you do NOT want gummosis.. do NOT plant a Prunus .. and it has nothing to do with the hole.. or the soil ... its a systemic disease .. inside the plant... and it hits all prunus.. period ...

it is NOT a fungus ... perhaps if you do some reading at the link.. you can better understand gummosis... and alleviate your concerns ...

ken

ps: neither the willow.. nor the CM is a Prunus....

Here is a link that might be useful: link