Juncus effusus

Common Rush

Soft Rush, EJSR Photo

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The natural history of the northwoods



  • Juncus, from the Latin, junceus, "rush"
  • effusus, from the Latin, "loose"
  • Common Name from
  • Other common names include: Soft Rush, Luachair Bhog (Gaelic), Harilik luga, kőrges, lambaluded, luht, sookaislad, konnaosjad (Estonia), Sitina Rozlozitá (Slovak)


  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Liliopsida, the Monocotyledons
      • Subclass Commelinidae
        • Order Juncales, the Rushes
          • Family Juncaceae, the Rushes
            • Genus Juncus, the Rushes
            • Subgenus Genuini
  • Taxonomic Serial Number: 39232
  • Also known as Juncus conglomeratus, Juncus effusus var. brunneus, Juncus effusus var. caeruleomontanus, Juncus effusus var. conglomeratus, Juncus effusus var. costulatus, Juncus effusus var. dicipiens, Juncus effusus var. exiguus, Juncus effusus var. gracilis, Juncus effusus var. pacificus, Juncus effusus var. pylaei, Juncus effusus var. solutus, Juncus effusus var. subglomeratus, Juncus griscomii, Juncus pylae.
  • The Juncus effusus complex has been variously recognized as containing several species or a single species with numerous infraspecific taxa. Unfortunately, North American treatments have dealt primarily with taxa in either the eastern or western portions of the continent. In considering the continent as a whole, little sense can be made of these treatments. The North American J. effusus complex is one that is in obvious need of modern systematic scrutiny.


  • A tufted, rhizotomatous, perennial herb of shallow water, 4--13 dm.
  • A ¼, ½, ¾, º, é
  • Leaves absent
  • Stem hollow, erect, and smooth, up to 4½' tall. Culms erect, terete, 1--2.5 mm diam. at top of sheaths. Cataphylls several.
  • Roots Rhizomes short -branched, forming distinct, often large clumps.
  • Flowers green/brown, about 1/6" long, several to a cluster, arising from the stem a few inches below the top. Inflorescences lateral, compound dichasia, many flowered; primary bract erect, terete, extending well beyond dichasium.
    • Sepals 3, free from each other, narrow, tapering to a point. tepals tan or darker, usually with greenish midstripe, lanceolate, 1.9--3.5 mm; inner slightly shorter;
    • Petals 3, free from each other, narrow, tapering to a point.
    • Stamens 3
    • Ovary superior (within blossom)
  • Fruit a smooth, brown/tan, obovoid capsule, about 1/6" long; containing numerous tiny seeds.
  • Seed amber/straw-colored, 1/40" long.
  • 2n = 40, 42.


  • A waterside plant
  • Distinguished from
  • The only Juncus with the flowers appearing lateral on the stem and no leaves.


  • Labrador to Alaska, south to Florida, Louisiana, Texas, and California.


  • Wet ground, in ditches, swamps, marshes, around ponds and lakes.
  • Swamps and their edges, marshes, moist meadows, and moist or saturated soils, often conspicuous in pasture meadows where it is shunned by grazing animals.


  • Trees: Tammarack (Larix laricina), Black Spruce (Picea mariana)
  • Shrubs: Bog Birch (Betula pumila), Leatherleaf (Chamaedaphne calyculata), Sweet Gale (Myrica gale)
  • Herbs: Cattails (Typha spp)
  • Ground Covers: Sphagnum Mosses (Sphagnum spp.)
  • Mammals: Moose (Alces alces), Muskrats sometimes eat the stems
  • Birds: Great Blue Heron (Ardea herodias), the seeds are eaten by waterfowl.




  • Reproduces by seed and vegetatively by rhizomes
  • Flowers May-SeptemberFlowering summer, fruiting summer--fall.


  • By rhizome division,


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Cultural Requirements
    • Sun
    • Soil
    • Water
    • Spacing
    • Fertilization
  • Size 12"-18"W x 12"-18"H
  • Growth rate
  • Good for
  • Cultivars include
  • Cultivars and species available by mail order from specialty suppliers or at local nurseries