Semera SC Herbicide is not labeled for Japanese hops. According to this article by Missouri Department of Conservation, pre emergents containing the active ingredient sulfometuron methyl (Oust XP) in mid March can provide pre emergent control  followed by a foliar application of glyphosate or metsulfuron applied prior to seed production (mid-April to August) may provide the most effective control. Subsequent applications will be necessary to control germinating plants throughout the season to prevent seed production. Please NOTE: Oust XP does not specifically list Japanese Hops as a weed controlled on the product label therefore you will need to contact the manufacturer directly or your County Extension Office for application rates and more information.