Corkscrew rush
Juncus effusus 'Spiralis' · Juncaceae
Leafless, dark green stems twisted into tight corkscrews and loose spirals, in a tangled mound. It grows in wet soil or shallow water.
- Size
- 16 in tall, 16 in wide
- Zones
- 5 to 9
- Light
- Full sun to part sun
- Flowers
- Grown for its leaves
- Pets
- No toxicity recorded
- Job in a bed
- Accent
A bed built around corkscrew rush
The planner designed this bed around corkscrew rush when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, full sun. It chose the other plants from the 251 that suit those conditions and its wet soil, and says below why corkscrew rush stands where it does.
The plants
- 1 Corkscrew rush × 2, dark green leaves
- 2 Stemless gentian × 21, blue
- 3 Himalayan fleeceflower 'Darjeeling Red' × 5, pink
- 4 White turtlehead × 5, white
- 5 Garden phlox 'David' × 3, white
- 6 Globe arborvitae 'Danica' × 1, green leaves
- 7 Camassia × 2, blue
- 8 Snowdrop × 12, white
Why this plant
- Grown for leaf, not flower. So is globe arborvitae 'Danica'. Leaf lasts all season, where a flower lasts a few weeks.
- Part of the bed's structure. Shrubs and grasses keep their shape when the perennials die down. So does globe arborvitae 'Danica'.
Why here
- In the middle. At 16 in it is the step between Himalayan fleeceflower 'Darjeeling Red' (10 in) in front and white turtlehead (3 ft) behind: each is seen over the one before.
- 2 plants in 2 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
Why now
- Here for its leaves, all year. They cover the 18 weeks between early March and late November when nothing on the plan is in flower.
- One of three evergreens. They are what the bed has to show from November to March.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 49% of the planted ground. A cool scheme: blue, pink and white. White is the colour seen most, on 3 of the 6 kinds grown for their flowers.
The planner's own design check: 10 Excellent, 6 Good, 1 Satisfactory. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where corkscrew rush goes in a border
At 16 in it belongs at the front of a bed. In the planner's ten height classes it is short (12 to 18 in).
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
A novelty that is best used singly, where its odd shape can be seen against plain water or gravel.
- A curiosity for pond sides and bog gardens
- Containers and water bowls
- Fun for children
What to plant with corkscrew rush
Plants recorded as good partners for it, and what each pairing does:
- Blue flag iris: adds the flowers, late May to late June; tall enough (2½ ft) to stand behind it; happy in the same wet soil.
- Marsh marigold: adds the flowers, mid April to early May; happy in the same wet soil.
- Sweet flag 'Ogon'.
Questions about corkscrew rush
Does corkscrew rush need sun or shade?
Corkscrew rush grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants moist to wet soil, rich in organic matter, and plenty of water. It copes with soil that stays wet.
What zones does corkscrew rush grow in?
USDA zones 5 to 9. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should corkscrew rush be planted?
16 in (40 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 16 in (40 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many corkscrew rush plants do I need?
At 16 in apart, set out in staggered rows:
- 7 to fill 10 square feet (about 1 m²)
- 8 for a single row 10 ft (3 m) long
- 21 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used two in two groups.
Is corkscrew rush poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat corkscrew rush?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
What does corkscrew rush look like in winter?
Corkscrew rush keeps its dark green leaves all winter, so it is one of the plants that hold a bed together from November to March, when the perennials have gone.
More Juncus
- Blue rush 'Blue Arrows' Juncus inflexus 'Blue Arrows'
- Soft rush Juncus effusus
In these guides
Every fact on record
- Type
- Grass
- Size
- 16 in (40 cm) tall, 16 in (40 cm) wide
- Plant
- 16 in (40 cm) apart
- Height class
- Short (12 to 18 in)
- Place in the bed
- Front
- Flowers
- None: grown for its foliage
- Leaves
- Fine texture, evergreen; dark green
- Shape
- Mounding, clumping
- Hardy in
- USDA zones 5 to 9
- Light
- Full sun, part sun
- Soil
- Rich, moist to wet
- Water
- High
- Feeding
- None needed
- Family
- Juncaceae
- Comes from
- North America, W. South America, Eurasia
- Stands up to
- Wet soil
Checked against NC State Extension. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.