Panicum gilvum Launert was first noticed in Belgium in 2007, but remained unrecognised for years due to confusion with P. dichotomiflorum. Although P. gilvum is a South African species, it is naturalised in Australia and was introduced into Belgium in 2024 as a grain alien from Australia. Its association with other Australian arable weeds found at the same site ultimately enabled its correct identification using Australian floras. In the summer of 2025, it became clear that P. gilvum is a well established species in Belgium which, like P. dichotomiflorum and P. schinzii, is mainly found as a weed in maize fields. This paper recounts at length the discovery of this species in Belgium – illustrative of the often belated discovery of a ‘new’ exotic species – and describes how P. gilvum can be distinguished from other naturalised Panicum species.