Rewetting of drained agricultural land is expanding across Europe to meet climate and biodiversity targets, yet the relative roles of post‐rewetting management and restoration age in shaping vegetation remain poorly resolved. We surveyed vascular plant communities and soils in 69 plots across 12 rewetted former croplands (6–22 years since rewetting) in Central to Northern Jutland, Denmark. Plots were subject to three management regimes: summer grazing, mowing or no active management. We quantified species richness, Shannon diversity, community uniquity (prevalence of regionally uncommon species), and the forb:graminoid ratio, and related these metrics to management, restoration age and soil conditions (pH, C:N ratio, plant-available P, Ellenberg indicators). Canonical correspondence analysis and PERMANOVA showed that management and soil gradients jointly structured species composition, with distinct assemblages in grazed, mown and unmanaged plots. Generalised linear mixed models revealed that summer grazing and mowing significantly increased plant species richness, Shannon diversity and community uniquity relative to unmanaged plots, whereas restoration age had no detectable effect on any vegetation metric within the 6–22 year timeframe. The forb:graminoid ratio was largely unaffected by management and increased with plant-available P. Our results indicate that, on intensively farmed soils, active management after rewetting is more important than time since restoration for promoting diverse, conservation-relevant wetland plant communities. Designing rewetting projects without explicit plans for grazing or mowing is therefore likely to limit biodiversity outcomes.