Ecological engineering is an emerging discipline where living design elements such as plants and microorganisms are used to solve engineering problems. Landfill phytocapping is an example of ecological engineering design, where instead of hydraulically containing waste materials with a compacted clay or geosynthethic cap, a soil-plant cover is installed instead to achieve the same objective. Landfill phytocaps, literally ‘plant caps’, consist of a layer of designed soil planted with a community of trees, shrubs and grasses. While they sound simplistic, they require deep integrated design thinking to ensure the cap functions as intended in an engineering sense, thrives as a living ecosystem over the long-term and maximises peripheral benefits to the community. This presentation outlines key considerations in ecological engineering using a phytocapping as an example. The general approach can be applied to other engineering technologies that employ plants as part of their design toolkit, such as water sensitive urban design (WSUD) and green infrastructure.