Mo. Rev. Stat. § 523.030
Upon the filing of the petition, a summons shall be issued, giving such owner at least ten days' notice of the time when said petition will be heard, which summons shall be served by the sheriff of the county, in the same manner as writs of summons are or may be by law required to be served. If the name or residence of the owner is unknown, or if the owners, or any of them, do not reside within the state, notice of the time of hearing the petition, reciting the substance of the petition and the day fixed for the hearing thereof, shall be given by publication once each week for three consecutive weeks prior to the time of hearing the petition, in a newspaper published in the county in which the proceedings are pending, if one is published in the county, or if no newspaper is published in the county, or the publisher shall refuse to publish the same on tender of his usual charges for advertising, then by posting up said notice for three consecutive weeks at the door of the courthouse of the county wherein the lands or any portion of them lie.
§ 523.030, RSMo