Mercurialietum annuae is the more thermophilous of the two asssociations of the alliance Veronico-Euphorbion occurring in the Czech Republic. It occurs in dry and warm lowlands in root-crop fields, vineyards, kitchen gardens, stubble fields and ruderal habitats. Soils are heavy, clayey to loamy and near-neutral to basic. Most species of this association are annual weeds which germinate in late spring; the phenological optimum of this association is in late summer.