Upon the filing of the petition a summons shall be issued giving such defendants named therein at least ten days’ notice of the time when the petition will be heard, which summons shall be served in the same manner as writs are or may be required to be served by the code of civil procedure. If the name or residence of any owners be unknown, or if the owners or any of them do not reside within the state, or if service upon them cannot be had for any reason specified in section 506.160, then service of notice of the time of hearing of the petition by mail or publication shall be made in the time and manner prescribed by said section 506.160. Notice of the proceedings shall be given to the owners of the property benefitted, as well as other parties interested, by publication as in this section provided for nonresidents except that such notice need not be addressed to them by name, but shall contain a general description of the property appropriated and of the benefit district by boundaries as defined by the legislative body. The notice to owners of property benefitted herein required may, in the discretion of the court or judge thereof, be incorporated in the notice by publication to unknown or absent defendants.