The association Rorippo-Phalaridetum includes vegetation dominated by Phalaris arundinacea, which occurs on stream banks, especially in the middle reaches of rivers, where it can also colonize sand and gravel bars in the river channels. Unlike in the association Phalaridetum arundinaceae, the water table remains largely below the soil surface, with flooding restricted to only a few days nearly every year. When they do occur, floods are strong, disturbing vegetation and removing fine particles from the substrate. This association is common in colline and submontane areas across the Czech Republic, and rarely occurs also on disturbed sites along lowland rivers.