The 1870 Census for Liberty, Yadkin, North Carolina has a John W Plowman, born abt 1856:

Wm Plowman, 35, Farmer,
Elvina Plowman, 34, Keeping House,
John W Plowman, 14, Farm hand,
Mary E Plowman, 11, No occupation,
James H Plowman, 9, at home,
Jesse Grant Plowman, 2, at home

Might be of use.

Stephen