Self-organised vegetation patterns arise in water limited systems as a result of the interaction of short range facilitation and long range competition. On smooth and gently sloped terrain banded vegetation patterns are known to spontaneously emerge as a result of these feedbacks. These ecohydrological interactions can also impact erosion and thus alter the long term variation in surface water redistribution patterns via changes to the topography. We explore the effect of this additional process on the geomorphology and spatial organisation of vegetation. The model is shown capable of reproducing banded vegetation patterns on a smooth hillslope in the absence of erosion. With significant fluvial erosion vegetation bands degrade and instead form a complex network of patchy vegetation colonizing main drainage channels. These channels in turn dissect a lumpy microtopography associated with the patches, containing a characteristic mound scale. This type of landform contains features resembling some real patchy semiarid hills. Decreasing the extent to which plants can locally increase soil hydraulic conductivity causes the resulting landform and vegetation pattern to be significantly different. Models investigating this co-evolution of form and function appear to offer new insights into the dynamics of water limited ecosystems.