The New Zealand Plant Conservation Network

Species

Schoenoplectus californicus

Common Name(s)

Californian bulrush

Authority

Schoenoplectus californicus (C.A.Mey.) Palla

Family

Cyperaceae

Brief Description

Tall (up to 4 m) dense clump forming rush, with no apparent leaves, dark green rounded stems (triangular near the base) and rusty brown scaly flower heads formed near the tip of each stem.

Flora Category

Vascular - Exotic

Structural Class

Sedges

Distribution

Restricted to Northern Wairoa River, Northland and Waikato River delta where it is abundant. A few other sites resulting from plantings.

Habitat

Coastal river banks and estuaries.

Features

A tall rhizomatous sedge 1-3 (-4.2) m x 10-35 mm, with green to dark green stems triangular near the base, round in upper parts. Leaves are reduced to brown papery basal sheaths. Inflorescence apparently sub-terminal dense; rays 4-10, pendulous, each with 1-5 spikelets on ultimate rays, primary rays usually 3-10 cm long. Spikelets rusty brown, ovoid-ellipsoid to cylindrical, 5-12 x 2.5-3 mm. Nut cream to grey, broadly obovate-elliptic, plano-convex, 2.9 x 1.7 mm.

Similar Taxa

The native sedge Schoenoplectus tabernaemontani. Key differences are the round bluish-green stem, smaller size and clustered, not drooping flower heads of this species. Schoenoplectus pungens (Vahl) Palla differs by its consistently triangular (in cross section) culms, and sessile 1-3 spikelets. Overall it is a much smaller plant than either of the other two species.

Flowering

November - April

Flower Colours

Brown

Fruiting

November to April

Year Naturalised

1992

Origin

Western North and South America, possibly eastern parts of the Pacific

Reason for Introduction

Accidental, likely through contamination of ballast

Control Techniques

Not usually controlled in New Zealand, but may be controlled manually, mechanically or herbicidally depending on situation.

Life Cycle and Dispersal

Long-lived perennial. Seed is viable, but seedlings have not been observed in the field. Movement of rhizome fragments by water is likely to be a major dispersal mechanism. Seed is long-lived, the surrounding bristles readily attach themselves to feathers, fur and clothing. This species was distributed in the past as a plant suitable for constructed wetlands to treat farm/domestic effluent.

Tolerances

Prefers brackish water, cold tolerant.

This page last updated on 26 Dec 2015