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Corkscrew Rush

Juncus effusus, Juncaceae

Sources last read 14 September 2026.

Not yet rated How forgiving it is has not been judged here yet.

Also called Common Rush, Green Bull Rush, pin rush, soft rush and sugar grass.

Corkscrew Rush (Juncus effusus), the whole plant.
Agnieszka Kwiecień, Nova, CC BY-SA 4.0 · Wikimedia Commons

Toxicity is partly unassessed

  • Not assessed for cats. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Not assessed for dogs. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Not assessed for people. RHS publishes no harm statement for this plant. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.

What the sources say about its care

Sources file this plant under other names: Juncus effusus 'Spiralis'. Citations below point at the name its source uses.

Light
Full sun, Full shade
RHS · read 13 September 2026
Water
Poorly-drained
RHS · read 13 September 2026
Humidity

No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.

ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%
Penn State Extension · read 13 September 2026
Temperature

How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.

H6 — -20 to -15°C -20 to -15 °C
RHS · read 13 September 2026
Soil
Clay, Loam; pH Acid
RHS · read 13 September 2026
Toxic to cats
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Toxic to dogs
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Harmful to people
No statement of harm to people is published for this plant; that absence is not evidence it is safe.
RHS · read 13 September 2026

Routine care

Watering
Can also be grown at pool edges in very shallow water.
RHS · read 13 September 2026
Propagation
By division.
NC State Extension · read 13 September 2026
Divide between mid-spring and early summer.
RHS · read 13 September 2026
Pruning
In spring, clear away old flowered stems and dead foliage.
RHS · read 13 September 2026
Pests and diseases
Usually free of pests and diseases.
RHS · read 13 September 2026

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About the plant

Juncus effusus is a perennial herbaceous flowering plant species in the rush family Juncaceae, with the common names common rush or soft rush.

From Wikipedia, CC BY-SA 4.0 · read 13 September 2026

Native range
Temp. Northern Hemisphere to W. South America, Rwanda to S. Africa, W. Indian Ocean
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
North America, W. South America, Eurasia,
NC State Extension · read 13 September 2026
Cosmopolitan
RHS · read 13 September 2026
Climate
temperate
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Growth form
perennial
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Herbaceous Perennial; habit clumping, erect, spreading
NC State Extension · read 13 September 2026
Clump forming (evergreen)
RHS · read 13 September 2026
Size
Height 12–36 in
NC State Extension · read 13 September 2026
Height 1-1.5 metres; spread 0.5-1 metres after 2–5 years
RHS · read 13 September 2026
Flowering
Flowers brown/copper, gold/yellow; blooms in summer
NC State Extension · read 13 September 2026
Flowers brown in spring and summer; green in spring and summer
RHS · read 13 September 2026
Uses

What sources record people using this plant for. A traditional or medicinal use listed here is a record of use, not advice to eat it or treat anything with it.

Bogs, wetlands
NC State Extension · read 13 September 2026

Plants with similar care

Sources

What this does not cover

The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.

Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.

If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.