The 22-year-old was arrested in the Mvoti area in Dalton, Lieutenant Joey Jeevan said.
The armed man and two others allegedly went to the Boiling Fountain farm on Friday and demanded cash from the 44-year-old wife.
Her husband, Bruno Muhl, 50, was shot and wounded in the chest when he arrived home.
The gunmen ran away with an undisclosed amount of money. Muhl was being treated in a local hospital.
The arrested man would appear in the New Hanover Magistrate's Court on a charge of attempted murder. The other two were still at large.