Robert H. Mohlenbrock @ USDA-NRCS PLANTS Database / USDA SCS. 1989. Midwest wetland flora: Field office illustrated guide to plant species. Midwest National Technical Center, Lincoln. Path rush is tough and adaptable, can be used as a ground cover for erosion control and soil stabilization.
FIRST IMPRESSIONS: Juncus tenuis is a diminutive rush that grows in dense clumps of upright cylindrical stems. Inconspicuous leaves are initiated near the ground at the stem base. In late spring, greenish brown inflorescences are borne on the stems in terminal clusters. Juncus tenuis is such a widespread and adaptable rush that it is considered by some to be weedy. This cool season perennial thrives in sunny or shaded moist or wet sites.
HABITAT & HARDINESS: Juncus tenuis is native throughout the United States and in most of Canada. The species has been introduced from North America into Eurasia and Australia.
This rush is indigenous to open woodlands, gravelly seeps, swamps, thickets, meadows, compacted foot paths, parking lots, fields, pastures, barren waste areas and roadsides. Plants are most common in freshwater sites that are saturated during winter and drier during the growing season or in disturbed habitats with compacted soil.
Hardy from USDA Zones 3-9.
PLANT DESCRIPTION: Juncus tenuis is a rhizomatous cool season perennial rush.
The prominent rounded stems or culms are semi-evergreen and arranged in dense tufts. They are medium green, smooth, erect and unbranched. Linear flat leaves originate from the stem base and are much shorter than the culms.
In summer the fertile culms terminate in a green umbel like inflorescence that is 1-3" wide. Each inflorescence averages fewer than 10 florets and has 3 slender leafy bracts that extend beyond the florets.
The florets transform into small brown egg shaped capsules full of tiny seed.
Plants are 6-24” tall with an equal spread.
CULTURAL & MAINTENANCE NEEDS: Juncus tenuis thrives in full sun or lightly shaded sites with wet to mesic soil.
Plants prosper in heavy clay and gravelly soils. They tolerate drought, flooding, moderate salinity, compacted soils and foot traffic.
This rush is pest resistant and unpalatable to deer and other herbivores.
LANDSCAPE USES: Juncus tenuis can be planted along pathways or as an effective Groundcover for Wetland Restoration Projects. Plants provide Erosion Control to Bioswales, drainage ditches, shorelines and are practical choices for Wet Meadows, Rain Gardens, Stormwater Management Projects and Deer Resistant Plantings.
COMPANION & UNDERSTUDY PLANTS: Juncus tenuis can be planted in a rain garden with Acorus americanus, Asclepias incarnata, Carex emoryi, Lobelia cardinalis, Iris versicolor, Iris virginica, and Scirpus cyperinus.
Juncus effusus is a larger species that is similar in appearance and cultural needs.
TRIVIA: Commonly known as “Path Rush” due to the plant’s ability to grow in the compacted soils associated with foot paths. Plants produce tiny seed that are sticky when wet. The seed cling to animal fur, vehicle tires and shoes and are distributed to paths and roadsides.
Occasionally called “Wiregrass” due to the tough narrow stems and grass-like demeanor.
Juncus tenuis can be easily distinguished from other low growing Juncus spp. due to their unusual bracts that are longer than the inflorescence.
True grasses (family Poaceae) have cylindrical jointed stems. The sedges (family Cyperaceae) have triangular stems. Rushes (family Juncaceae) have cylindrical unjointed stems.
Budding Botanists often learn the rhyme “Rushes are round and sedges have edges”. This refers to the cylindrical stems of Juncus spp. and the triangular stems and entire leaf margins of Carex spp.
Juncus tenuis provides cover and nesting sites for wetland birds and other wildlife.