Ah...Covered by the Period Clause.
Thomas Jefferson, who felt that the procedure (of annual address to Congress) resembled the speech from the throne delivered by British monarchs, chose instead to send written messages to Congress for reading by clerks. Jefferson’s procedure was followed by future Presidents until Woodrow Wilson reverted to the former procedure of personally addressing Congress, which has continued to this day.That is how Wikipedia renders it, and it reveals how Wilson saw himself. Nothing prohibiting any variation from an address to Congress.