This sedge looks very much like another tall native sedge, Scirpus validus, soft-stem bulrush. Scirpus californicus is occasionally found growing in ponds, marshes and streams from the northern counties south to the central peninsula (Wunderlin, 2003). It blooms from spring to summer and occurs almost always under natural conditions in wetlands.
Southern bulrush is a bulrush sedge from knotty rhizomes; stems to 10 ft. tall, dark green, smooth, slightly 3-angled; leaf blades none, just sheaths; inflorescence at stem tip but appears to be on the side of the top of the stem, irregular drooping branches, each branch having brown spikelets; bract rolled, pointed, to 3 in. long, appears to be continuation of stem; spikelets narrow ovoid, numerous, dark brown, to 1/2 in. long; nutlets grayish, feathery bristles, 2-4, dark red