Much more than bees—Wildflower plantings support highly diverse flower-visitor communities from complex to structurally simple agricultural landscapes

•75% of all insect flower visitor species on wildflower plantings were neither bees nor hoverflies.•Even low levels of flower richness were sufficient to support high visitor richness.•With the exception of wild bees, visitor richness was high also in simple landscapes.•Specialist taxa benefit most from establishing multiple locally connected plantings. One goal of wildflower plantings is to promote biodiversity in intensively managed agricultural landscapes. Flower visitors of wildflower plantings encompass many ecologically and economically important species. However, most studies on flower visitors of wildflower plantings have focused on single or few prominent taxa (e.g., wild bees and hoverflies). In contrast, it remains largely unresolved how non-prominent flower visitors of the community are affected by wildflower resources, landscape context and time of the flowering season. We studied highly diverse flower-visitor communities on 14 wildflower plantings varying in flower abundance and richness and their surrounding landscape context within a 500m radius (percentage arable land, presence of additional wildflower plantings). Flower visitors were sampled in the early (May–June) and late (June–July) flowering season and grouped as follows: managed honeybees, wild bees, hoverflies, all other flower visitors. Strikingly, only 81 (25.1%) of all 322 visiting species (