California Bulrush

California bulrush (Schoenoplectus californicus) is a common plant in freshwater marshes. Leaves are greatly reduced, and a plant consists of tall green stems, topped with brown tassels of flowers and seeds.

The Kumeyaay harvested the tender young shoots for food and used the stems for a variety of construction projects, from ropes to boats.

Although it will tolerate some salinity, most of our bulrush is found east of Interstate 5, where the ocean influence is muted. Large stands are visible from the East Basin trails. California bulrush is also found in Central Basin in areas kept wet by local freshwater runoff – along the Pole Road and east of the Nature Center boardwalk.

Description ^2,4,3,11

California bulrush is an upright perennial, usually less than 8 feet (2.5m) tall. Leaves are inconspicuous, reduced to short, clasping structures at the base of the stems. The “foliage” is composed of unbranched, vertical green stems from subsurface horizontal rhizomes. Stems are rounded-triangular in cross section, especially near the top. The interiors of the stems are porous.

Each flower head appears as a tassel near the top of a stem. What seems to be a short section of stem extending beyond the tassel is actually a bract. Each tassel consists of numerous cone-like spikelets which hang from short, arching branchlets. Lower tassels may have 20 or more spikelets. Flowers are bisexual. Petals and sepals are reduced to 2-4 tiny strap-shaped structures with soft hairs along the margin. These persist at the base of the fruit, but are difficult to see without magnification. Stamens and pistils emerge from clasping, reddish-brown scales. There are two stamens and a single pistil with a branched style. The major bloom period is in the summer.¹

The fruit is a dry, hard achene less than ¼ inches (2.2 mm) in length. There is one seed.

Classification ^2,7

California bulrush is a perennial monocot in the sedge family (Cyperaceae). In spite of the name “bulrush”, it is not closely related to rushes, which are in a different family separated by the structure of the flowers and fruit, and by the internal structure of the stems.

Until recently, California bulrush was placed in the genus Scirpus.

Two other species of Schoenoplectus have been reported from the Reserve, hardstem bulrush (S. acutus) and Olney’s bulrush (S. americanus).⁴⁸ Although superficially similar, they are not difficult to distinguish.

Ecology

California bulrush is one of a group of marsh plants called “emergent vegetation”. These are plants, such as cattails, cord grass and rice, which have their roots submerged and their vegetative and reproductive structures above water.¹²⁴ The roots of such plants require oxygen for growth and function, but the sediment which surrounds them is characteristically low or lacking in oxygen (anoxic). Emergent plants have a system of elongated, hollow cells within the leaves and stems (aerenchyma). These run to the roots providing diffusion channels that transfer oxygen from the atmosphere through the vegetative structures to the roots (somewhat like snorkels); at the same time excess carbon dioxide from the roots diffuses in the opposite direction.⁴¹

Recent research suggests that air may diffuse into the sediment from the roots, creating small oxygenated pockets that support aerobic bacteria. These bacteria enhance nutrient uptake and the sequestration and decomposition of pollutants.^104,105 Much of the water purification that occurs in a marsh may take place in these bacterial pockets.

Human Uses

Coastal California Indians harvested the tender young shoots of bulrush for food and used the stems and leaves for a variety of construction projects, from ropes to roofs.^34,95 Throughout California and Baja California, “tules” (primarily California and hardstem bulrushes) were important in the construction of boats.^34,75,95 The Chumash Indians of the Channel Island – Ventura region made a shallow boat by preparing “three or five bundles [of green stalks] that were stiffened with willow poles and bound together.” It was waterproofed with tar and rubbed with fine clay to remove the stickiness.¹⁵ Other tribes caulked the boat with the pith of tules.⁷⁵ A replicated Kumeyaay boat of similar construction hangs in our Nature Center.

Bulrush has been shown to facilitate the removal of excess nutrients from contaminated water,¹⁰³ although the exact mechanisms by which this purification occurs are debated.¹⁰⁴ It was hypothesized that bulrush along the Louisiana coast might be important in reducing the effects of the 2010 oil spill in the Gulf of Mexico,¹⁰⁵ but we don’t know whether they were tried or if they helped.

Interesting Facts

The dense, upright foliage of California bulrush provides food shelter and nesting habitat for birds, mammals, reptiles and amphibians, making emergent vegetation (which includes other bulrush species and cattails) one of the most productive wildlife habitats in California.⁶⁷

The bulrushes that sheltered Moses were probably not the same genus as our bulrushes but the distantly related paper reed (Cyperus papyrus).⁴¹