The Key Differences Between Grasses and Sedges

Grasses and sedges are common plants found in many lawns and gardens. Though they look quite similar at first glance there are some key differences between grasses and sedges.

Stems

One of the most noticeable differences between grasses and sedges is in their stems.

Grass stems are hollow except at the joints or nodes. The nodes are the swollen rings that encircle the stem at intervals. Grass stems are typically round or flattened.

Sedge stems, on the other hand, are solid, not hollow. Sedge stems are often triangular in cross-section, which gives rise to the mnemonic “sedges have edges.” Sedge stems do not have nodes like grass stems.

Leaves

The leaves of grasses and sedges also differ.

Grass leaves are elongated and blade-like in shape with parallel veins. The leaf sheaths wrap around the stem but are open on one side.

Sedge leaves are also blade-like but are typically shorter than grass leaves. Sedge leaf sheaths are closed around the stem. In some sedges the leaves are arranged in three ranks along the three angles of the stem.

Flowers

The flowers of grasses and sedges are quite different.

Grass flowers are arranged in spikelets which collectively make up the inflorescence or flower cluster. Each tiny grass flower is surrounded by two bracts called palea and lemma.

Sedge flowers are very small and inconspicuous, arranged in spikes. Each tiny sedge flower is surrounded by a sac-like structure called a perigynium.

Roots

Below ground, grasses and sedges have fibrous root systems. But grass roots tend to be shallower while sedge roots grow deeper in the soil.

Habitats

Though grasses and sedges overlap in some habitats, they have some differences in preferred growing conditions.

Grasses thrive in full sun and disturbed soils. Many common lawn and pasture grasses tolerate drought and trampling.

Sedges prefer part shade to full shade. They tolerate moist soils and are often found near water or in wetlands. Their tolerance for wet soils makes them useful for rain gardens, pond edges, and drainage areas.

Uses

Both grasses and sedges have many uses, though grasses are more widely cultivated.

Grasses are the basis for lawns, pastures, meadows, and cereals like wheat, rice, corn, and oats. Bamboo, sugar cane, and sorghum are also grasses. Ornamental grasses add texture and color to gardens.

Sedges are used for erosion control, rain gardens, pond edges, and shade gardens. They work well as ground covers. A few sedges produce edible tubers. Ornamental sedges add fine textures and colors to shady areas.

How to Tell Them Apart

Telling grasses and sedges apart does take some practice. But a few tips can help:

• Feel the stem – is it hollow or solid? Triangular or round? Look closely for nodes on grass stems.

• Examine the leaves – are the sheaths open or closed? How many ranks of leaves are there?

• Consider the habitat – is it sunny or shady? Wet or dry soil?

• Look at the flowers – are they in spikelets or spikes? Do you see papery bracts or sac-like perigynia?

With close observation and experience, distinguishing between grasses and sedges will become easier. Getting to know the common grasses and sedges in your area is the best way to hone your identification skills.

So next time you are tempted to call any grass-like plant just “grass,” take a second look. It may actually be a sedge! Understanding the differences between grasses and sedges will deepen your knowledge and appreciation of these common plants.