Spreading rush (Juncus patens) is a common perennial plant. This grass-like species is recognized for its unique form and adaptability. While it offers ecological benefits in natural settings, it can become a management concern in cultivated areas.
Identifying Spreading Rush
Spreading rush forms dense, evergreen clumps. Its thin, rounded stems are gray-green to blue-green, often waxy. These upright, leafless stems reach 1 to 3 feet tall and spread 1 to 2 feet wide from short rhizomes.
Small, inconspicuous golden-brown flower clusters emerge from the side of the stems, not the tip, from spring through autumn. After flowering, the plant produces spherical red or brown seed capsules. Its architectural form provides a fine texture that contrasts with broader-leaved plants.
Where Spreading Rush Thrives
This rush species is native to the West Coast of the United States, from Washington to California and into Baja California, Mexico. It thrives in moist environments, commonly found in wetlands, streambanks, riparian zones, seeps, and marshes.
It adapts well to high soil moisture, tolerating both standing water and periodic dry spells once established. While it prefers moist to wet soils, it grows in various soil types, including loam and clay, and tolerates full sun to partial shade.
The Impact of Spreading Rush
Spreading rush can concern gardeners and landowners, especially in cultivated landscapes. Its rhizomatous nature allows it to spread aggressively, outcompeting desired ornamental plants or turfgrass and encroaching upon garden beds.
In agricultural settings, particularly irrigated pastures, dense infestations can reduce the quantity and quality of available forage for livestock. The plant’s presence also indicates poor drainage. Despite these challenges, spreading rush offers ecological benefits in natural settings, such as erosion control and providing habitat and shelter for wildlife.
Managing Spreading Rush
Management of spreading rush involves cultural practices, manual removal, and chemical control. Addressing underlying environmental conditions that favor its growth is a primary step. Improving soil drainage by amending heavy, poorly draining soils or installing drainage systems reduces the moist conditions that allow the rush to flourish.
For smaller infestations, manual removal by digging out individual clumps is effective. Remove as much of the rhizome system as possible, as the plant regenerates from remaining root fragments. Mowing or cutting temporarily reduces its presence but is not a long-term solution, as the plant quickly recovers and re-establishes from seeds or rhizomes. If mowing, cut before seeds become viable in late spring or early summer to limit spread.
Chemical control is an option for larger or more persistent infestations. Systemic herbicides like glyphosate are effective when applied to actively growing rush plants. As glyphosate is a broad-spectrum herbicide, avoid contact with desirable plants. Applying it with a weed wiper allows for targeted treatment, minimizing harm to surrounding vegetation. Another option is 2,4-D, a broadleaf-selective herbicide, applied post-emergence in mid to late spring. Always consult and follow product label instructions carefully, especially regarding application rates, timing, and safety precautions near water sources.