City taxes shall be due on the first day of July of the year when levied. The Treasurer shall not be required to call upon the persons named in the City tax roll, nor to make personal demand for the payment of taxes, but he shall give notice to the taxpayers of the City by publication in a newspaper at least twice, the last of which publication of notice shall be made at least ten days prior to the first day of July in each year, of the time when said taxes will be due collection, or shall give such notice by first class mail addressed to the owners of the property upon which taxes are assessed according to the names of such owners and their addresses as indicated on the tax roll, which notice shall be deemed sufficient for the payments of all taxes on said roll. Failure on the part of the Treasurer to give said notice shall not invalidate the taxes on said tax roll nor release any person or property assessed from the penalty provided in this Charter in case of nonpayment of the same.