By low maintenance I read this as watering? Well, the most low maintenance plants are succulents (including several Cacti). They range in size from huge plants like Agave's and some arborescent stem succulent Euphorbia's and Opuntia's right down to smaller plants such as fleshy leaved Sedums, Carpobrotus and Crassula's with everything in size between. They cover a wide range of plants and include colourful plants such as many Pelargoniums which many people are familiar with.