What Is Corkscrew Rush Plant?
Twisted or "Corkscrew" rush is called Juncus effusus by botanists. In the North, the plant is an herbaceous perennial (prune off the browned stems in early spring). In hotter regions, it is semi-evergreen; in fact, it can even be invasive in some of the warm climates, due to its ability to spread via rhizomes.
A number of cultivars are on the market, offering variations in height.
- J. effusus 'Curly Wurly' (up to 8 inches tall)
- J. effusus 'Big Twister' (up to 1 foot tall, but often stays shorter)
- J. effusus 'Spiralis' (12-18 inches tall)
- J. effusus 'Quartz Creek' (18-36 inches tall)
Crazily twisted stems spiral out of control from their clumps in ways that are sure to delight all who have an appreciation for whimsy in the landscape. The curly stems of this foliage plant are dark green in color, making them a good foil for foliage of a lighter color.
Preferred Growing Conditions, Care
Corkscrew rush plants are often listed as perennials for planting zones 4 to 9, but there isn't much consensus on this point. Some sources say the plants are cold-hardy only to zone 6. Indeed, one winter I lost a corkscrew rush here in zone 5.
Grow these perennials in full sun (partial shade in the more southerly zones). The main thing to remember is that they like wet soil, regardless of soil type.
Since the species plant, Juncus effusus (see below) often grows at the edges of marshes or even a few inches into the water, you know they will tolerate boggy soil. Either a neutral or an acidic soil pH is fine.
Little care is required to grow this plant. Apply an all-purpose fertilizer or manure tea in spring.
Prune away stems that have browned. Happily, these are deer-resistant perennials.
Best Landscaping Use: in Water Gardens
Because of their ability to grow in a few inches of standing water, corkscrew rush plants present you with a couple of options when assembling water gardens:
- Grow them in containers, which can be sunken into the water (just don't bury the crowns more than 3-4 inches)
- Grow them in the ground around the margins of the water feature
If you can spare a few stems, cut them and add them to a floral arrangement, where they will provide just as much as pizzazz as they do in your water garden. They are highly architectural plants and make a powerful statement in almost any situation.
More About the Species Plant (Juncus effusus)
The species plant that grows wild across much of the world bears the common names "soft rush" and "common rush." J. effusus is native to North America and various other continents. It grows in clumps to a height of 2-4 feet with a similar spread. Common rush produces clusters of small, greenish-yellow flowers throughout the summer.
But the wild version lacks the spiraling stems that make the cultivars, J. effusus 'Big Twister,' J. effusus 'Spiralis,' etc.
such highly ornamental landscape plants. Common rush has rather uninteresting, straight stems. It grows in full sun and in wet ground (even in shallow standing water). A rhizomatous plant, it is useful for soil erosion control.
A shorter type of wild rush (1 foot tall or less) that I consider a weed in my own landscaping is path rush (J. tenuis).True to its common name, it thrives in the compacted soil of the path that parallels my driveway. In his highly useful weed-identification book, Wild Urban Plants of the Northeast, Peter Del Tredici quips, "Path rush is one of the few plants treated in this book for which humans have found few uses" (p.300).
How Do Rushes, Sedges, and Grasses Differ?
Because most people are familiar with the concept, "grass" and unfamiliar with the concepts of "rush" and "sedge," plants in the latter two categories are often misidentified as grasses.
Here's a basic breakdown of the three plant families:
- Sedge family (Cyperaceae): stems have three edges (i.e., they're triangular in cross-section)
- Rush family (Juncaceae): stems are typically round
- Grass family (Poaceae): stems tend to be more flattened
Examples of sedges are: