landscapers often put plants on the ground and build up soil around it. You could half bury it and get 5-10 gallons of dirt and make a small mound if you're that worried.
I've had trees around puddles for days come out just fine.
Dont make the soil loose, pack it down some as you put it back. I keep my fingers open and push the soil down with my fingers. The stuff around the roots I make sure its real fine so it can go around the roots. I usually make a small lump and spread the roots around the lump. Cuts down on the air pockets and creates less root damage while compacting it.
When done I wet real good, then pump the top of the soil with my hands. The fine bits of clay seal up the small cavities.
I'd also wait a week or two before covering with mulch. Help it dry out some, but cover it before summer comes.