Grimes Meadow, consisting of two lowland flood meadows straddling the river Windrush, is a designated Local Wildlife Site. The Wychwood Forest trust acquired this reserve in 2011 with generous support from the Patsy Wood Trust. Though Grimes Mead and Little Grimes are now enclosed by the town of Witney, maps from 1797 show the area was once an open landscape. Field boundaries were marked by ditches, and watercourses lined by traditionally pollarded willows. Grimes' character has remained much the same for at least two centuries: unimproved neutral grassland and a sedge-dominated swamp community bordered by impressive willow trees.
The Trust manages Grimes Meadow for its ecological and historic importance: pollarding willows in rotation; maintaining sward height of grasses, sedges and rushes; repairing and maintaining boundary fencing; and monitoring and surveying the site. The reserve is a key component of the Windrush floodplain, a green corridor that runs through the centre of the historic market town.