The Difference Between Grasses and Sedges :
As grasses, sedges, and rushes are often referred to as ‘ornamental grasses’ this is because they can all be used to provide a wide range of unique textures, with varying degrees of movement, while adding to the surrounding architecture with their range of colour and sound. Although they are often visible all year round in any landscape, the general rule is that the grasses prefer the sunny areas of the landscape with the well drained soils where as the sedge and rush often thrive in the most shady and moist locations available.
Grass/Rush can either be annuals or perennials, whereas all Sedges are perennial.
To identify these, the stems of both sedges and rushes are generally solid, where as the grass is hollow, and the stem, If you look closely, you can distinguish each from the other by structural differences as well as by general differences in their native habitat and distribution.