Since 2003 the Eno River Association has worked with the NC Plant Conservation Program and NC Botanical Garden on the Diabase Sill Project Partnership. This Partnership is named for the distinct geological formation of hard igneous rock found within the Lower Eno River basin in Durham. The basic soils weathered from the underlying Diabase rock have heavily influenced the area’s topography and ecology, supporting a highly diverse and rare community of plants.
Two rare plant preserves totaling over 350 acres have been protected as part of the Partnership: the Eno River Diabase Sill Rare Plant Preserve and the Hebron Road Rare Plant Preserve. Both of these preserves are owned by the NC Plant Conservation Program and can be accessed by special permit or guided tour.