No judgment shall be rendered against a garnishee on a pleading which controverts the garnishee's answer until notice of the filing of the controverting pleading and of the time and place of trial thereon is served on the garnishee for such time and in such manner as the court or judge shall order. A garnishee who has been so notified shall not be entitled to notice of the filing of amendments or of trial thereon.
Iowa Code § 642.12