Culture
Easily grown in moist to wet soils in full sun to part shade. Best in full sun. Performs well in standing water to 4” deep, but will also grow well in garden soils as long as the soils are in fact kept consistently moist. Plants will spread in the landscape by rhizomes and by self-seeding. Rhizomatous spread may be controlled, if desired, by growing this plant in large containers sunk in the ground. Foliage remains evergreen in warm winter climates or when grown indoors as a houseplant. In St. Louis, outdoor clumps die to the ground in winter. Old foliage should be cut back in early spring. Propagate by seed or division.
Noteworthy Characteristics
Juncus effuses, commonly known as soft rush, common rush, bog rush or mat rush, is a grasslike-like, rhizomatous, wetland perennial that features smooth, upright, cylindrical, unjointed, spire-like green stems (leaves are absent) which grow in spreading basal clumps to 20-40” tall. It is one of the true rushes. It has a nearly cosmopolitan distribution, being found in many places around the world, but primarily in cool-temperate regions, particularly ones having wet soils. It is often found growing in ditches, bogs, swamps, marshes, wet pastures, and along the margins of lakes and rivers. It is infrequently found growing in tropical areas. Stems are usually solid, with the leaves typically reduced to bladeless basal sheathes. Insignificant, minute, yellowish-green to pale brown flowers bloom in one-sided clusters (many-flowered cymes) located on stem sides slightly below the stem tips. Flowers emerge in summer (July to September). Fruit is an obovoid capsule. Clumps provide vertical accent to moist garden areas. Although the stems appear from a distance as coarse and stiff, they are soft to the touch. Soft rush is considered to be a somewhat invasive weed in a number of locations. Foliage turns yellow in fall before browning up for winter.
Forma spiralis, commonly known as corkscrew rush, features a tuft of cylindrical, tightly spiraled, corkscrew-like green stems (to 1/4” thick) which uncoil as they grow and spread out in all directions (both upright and prostrate) forming a somewhat contorted and tangled foliage mass. Clumps typically grow to 14-18” tall with a similar spread. Minute brown flowers (to 1/8” long) bloom in loose cymes (to 2” long) in summer.
Genus name means rush.
Specific epithet means loose-spreading in probable reference to plant habit.
‘Unicorn’ is a corkscrew rush cultivar that was selected by the University of British Columbia. It is a vigorous plant featuring stems which are taller (plants grow to 18” tall with a slightly wider spread), slightly more twisted, and darker green than those stems found on f. spiralis plants.
Problems
No serious insect or disease problems. Rust, leaf spot and stem rots may occur.
Uses
Except for certain horticultural varieties, straight species plants are typically not grown as garden plants. They may be grown at the edge of a pond or water garden, in boggy areas, among wet pebbles or rocks or in several inches of standing water. Good water garden accent. Effective in containers. Interesting plant for transitional waterside areas. May help control soil erosion on moist banks.
Corkscrew rush is an attractive plant that provides both unique texture and remarkable contrast to garden areas. Interesting plant for shady pond margins, courtyards, and patio containers. Twisted stems are often added, fresh cut or dried, to floral arrangements. Excellent evergreen container plant which can be brought indoors in winter or kept indoors year round as a houseplant.