Sourwood (?) Tree Leaves

Change.  It's in the air.  It's also on the ground.  The photo indicates days are shortening.  I believe these are sourwood seedlings.  I know sourwood tree leaves turn red very early and here it is not quite August.  And it's usual to see some red and some green together even on the same tree.   I'd like to have one of these trees in my yard.  Perhaps I'll try digging one up from the ditch where I found these on my morning walk.  I can determine whether or not it is sourwood by tasting one of the green leaves.  Tastes sort of lemony.  When I walk in the morning, I'll test it.