Spartina alterniflora is a perennial grass that expands via underground rhizomes. It is native to the eastern United States, but is considered invasive, in salt marshes, in California. Hollow stems grow from 2-4 ft. (0.6-1.2 m) tall.
Foliage
Leaves are 8-20 in. (20-50 cm) long, 1-8 in. (2.5-20 cm) wide and are often purplish at the base.
Flowers
Flowering occurs in July to November, when densely packed clusters of tan flowers develop.
Fruit
The fruit are flattened and smooth, with pointed tips. The plant also expands via underground rhizomes.
Ecological Threat
Spartina alterniflora was introduced on the west coast in the early 1970s to be used as erosion control. Plants have become extremely invasive in San Francisco Bay, Willapa Bay and Puget Sound.