Spike grass, an important sediment stabilizer in Rhode Island salt marshes. Courtesy: NOAA

Spike Grass (Distichlis spicata)

Alternate common name: Salt Grass.
Appearance: A grass that grows from 8 to 15 inches tall with a terminal flowering spike at its tip. Green in spring and summer, becomes light brown in fall and winter.
Habitat: High salt marsh.
Seasonal appearance: Blooms August to October.

Description

Spike grass is a short grass often found growing with salt hay grass in higher salt marsh zones. Before it flowers, spike grass is difficult to distinguish from salt hay grass. When in bloom, spike grass has a single, spindle-shaped flower head comprised of numerous individual flowers. Spike grass also has stiff, light green stems 8 to 15 inches high. Its stems are stouter than those of the wiry salt hay grass. At maturity spike grass is a dull green. Stems of this grass are usually hollow and erect, but winds and tides can bend them to form mats. Its leaves are also hollow and curl inward, appearing round, and radiate in several planes around the stem. Leaves can reach lengths of 2 to 4 inches.

Life History and Growth

Spike grass is a quick colonizer of bare patches, called pannes, in the marsh. Spike grass, living in a healthy section of the marsh, will send out root runners to the bare patches to expand and exploit the open space. The new shoot does not actually grow in the panne; it gets water and nutrients from the original plant. Over time the developing spike grass plants will create enough shade to reduce the impact of the sun on the sediment, allowing other marsh plants to recolonize the bare patch.

Spike grass provides a habitat for many invertebrates and is the base of the food chain, with the roots and young plants providing food for waterfowl, marsh birds, sea birds, and small mammals.

Special Notes

• A well-developed root system, high salinity tolerance, and the ability to colonize bare marsh peat make spike grass an important marsh stabilizer.
• Spike grass also helps to provide a shoreline buffer and to filter polluted run-off.
• Damage to spike grass through human activity leads to shoreline erosion, reduces the natural pollution filter system of a salt marsh, and destroys habitat.

Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.