Mo. Rev. Stat. § 235.050: Notice to be published, when.

Immediately after the filing of such petition, the county commission shall, by order, fix a time and place not less than thirty days nor more than sixty days after the petition is filed for a hearing thereon, and thereupon the county clerk shall cause notice by publication to be made of the filing of the petition and the pendency of the action and of the time and place of the hearing.