A flexible mailbox support is assembled by pivotable attachment of a mailbox support arm to a post having two rigid sections separated by a flexible middle section and coverable by a replaceable sleeve, the connection between the support arm and the post uses a single bolt inserted through and joining a flat surface on the arm to a flat surface on the top of the post, formed to be detachable with force, the parallel surfaces being set at an angle of less than 90 degrees from the post and a spring is compressed by the bolt head to adjustably bias the surfaces against one another while allowing the arm to pivot about the axis of the bolt, with a cage providing protection for the mailbox.