Vegetation ecosystem simulation and visualisation are a challenging topic involving multidisciplinary aspects. We present here a generic frame focused on functional plant growth models under environmental resource conditions: the growth model is coupled to the climatic conditions (temperature, rainfalls) and the competition between plants is taken into account, according to soil hydrological budget. A simple architecture and simulation scheme are proposed to synchronise the water cycles updating (daily based) and the plant growth cycles. A voxel space is used to store the water resource, and layers hold the interfaces between the environmental data and landscape components. The prototype simulator is operative on PC and HPCs with in-line and off-line visualisation tools. Despite the rough implementation level of the underlying bio-physical models, we have simulated realistic behavior of a simple vegetation model in heterogeneous environmental conditions, in space and time.