Peatlands are an important carbon (C) store but many have been drained and damaged by mechanical harvesting. Little is known about ecological processes on abandoned peatlands that have recolonized naturally nor the impact of plants on C balance of these sites. Over the course of 13 months, we measured amounts of litter falling from three different species colonizing an abandoned peat bog in north-eastern Scotland to calculate potential inputs of C and nitrogen (N). In parallel, a litter bag experiment quantified C loss from the litter of these species over 18 months. Calluna vulgaris produced the greatest amounts of litter (276 ± 32.3 g dwt m⁻² yr⁻¹); Eriophorum angustifolium produced 10.9 ± 2.6 g dwt m⁻² yr⁻¹ and Eriophorum vaginatum produced 42.3 ± 3.5 g dwt m⁻² yr⁻¹. Carbon loss varied from 30% (E. vaginatum) to 40% (Calluna) over 18 months, but differences among the three species were not significant. Overall, these findings indicate that Calluna can make significant inputs of C and N into degraded cut-over peatlands, but seasonal variation in inputs is considerable.