Grasses, Sedges and Rushes

When we refer to ornamental grasses, the term is used in a broad sense to include not only grasses but also many plants we think of as grasses which are actually only relatives of grasses or grasslike in appearance.  Three families comprise the bulk of the plants we call ornamental grasses, and these include true grasses, sedges and rushes.

True grasses are members of Gramineae, the grass family.  The stems of grasses are round in form and typically hollow with solid joints or nodes.  The leaf blades are flat.  Although their flowers are not typically showy like perennial flowers, they are showier than sedges or rushes.  They can be annual or perennial, evergreen or deciduous.  They grow in a wide range of soil and light conditions.

Sedges are in the Cyperaceae family and are more common in colder, wetter areas.   Most sedges belong to the genus Carex.  They are mostly perennial and evergreen.  They can often be identified by their solid, triangular (three-sided) stems.  Flowers are inconspicuous. Sedges are usually found in moist conditions.

Rushes belong to a small family called Juncaceae.  Their stems are solid and round with no joints.  Their leaves are round (cylindrical) and pointed. Flowers are inconspicuous. Most rushes are found in wet, boggy conditions.

An easy way to remember these differences is to use this little rhyme — “Grasses are hollow, sedges have edges, and rushes are round.”