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The California gray rush is native to the west coast of the United States where it grows in moist habitats where winter rains often collect. This species is well suited to seasonal bioswales and stream bed plantings where the soils can become saturated by winter rains. Established plants will adapt to low amounts of summer irrigation.

California gray rush is comprised of pale green cylindrical stems that grow 18-24 in. tall; brown flowers accent the plant in mid to late spring. Plants form dense clumps and slowly spread from rhizomes to form masses several feet wide.

Water Needs

The California gray rush is well adapted to bioswales with winter rainfall and low to moderate amounts of summer water. The chart shown below provides a recommended baseline guide to the monthly irrigation schedule and volume of supplemental water needed to maintain healthy growth throughout the average year. It should be noted there are several winter months marked by an asterisk (*) when rains can provide sufficient moisture and irrigation is not needed. The high and low range of moisture indicates it can grow with varying amounts of water; higher amounts of water within this range will help this rush grow best.

Irrigation Schedule and Graph

Moderate Water Use Plants

Irrigation Schedule 3

  Jan* Feb* Mar* Apr May Jun Jul Aug Sep Oct Nov* Dec*
Runs per Month 0x to 3x 0x to 3x 0x to 3x 2x to 3x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 1x to 2x 2x to 3x 0x to 3x 0x to 3x
Inches per Run 1" 1" 1" 1" 1" 1" 1" 1" 1" 1" 1" 1"
Inches per Month 0" to 3" 0" to 3" 0" to 3" 2" to 3" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 1" to 2" 2" to 3" 0" to 3" 0" to 3"

Range of supplemental summer water: 9"-16"
Range of supplemental winter water: 0"-15"

  Jan* Feb* Mar* Apr May Jun Jul Aug Sep Oct Nov* Dec*
For more information on how to use this Irrigation Schedule and Graph, follow this link.

For information how to calculate your irrigation system’s schedule and precipitation rate, please follow this link.

Plant Properties

Plant Type: Grass, Rush, Native
Foliage Character: Evergreen
Habit: Upright, Spreading, Dense, Clumping
Growth Rate: Fast
Height: 18 in. - 24 in.
Width: 18 in. - 24 in.
Water Needs: Moderate 3
Foliage Color: Pale green
Flower Color: Brown
Flower Season: Spring
Soil Adaptations: Moist soil
Exposure Adaptations: Morning sun, Moderate shade, Heat, Frost, All day sun
Function: Wildlife value, Restoration, Residential spaces, Mass planting, Grouped, Foliage accent plant, Commercial spaces, Borders, Background plant


This low maintenance plant is often maintained incorrectly. Never cut back plants part way. Juncus is a form of rush that, while grass like, is not a grass. Plants cut back part way generally dont look good. To maintain, as needed, prune out individual entire leaves to the ground if they have turned brown and look messy. If the entire plant looks like it needs refreshing, cut the entire plant all the way to the ground in the late winter to encourage vigorous new spring growth (D,S).



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