What a Rush! Ornamental Grasses That Is!

This article was originally published on May 17, 2012 and expired on July 15, 2012. It is provided here for archival purposes and may contain dated information.

Ornamental grasses are quite popular because of their color, texture, form, and winter interest, but there are other plants that can be equally interesting in the garden and that often get overlooked.

"They are the rushes," said University of Illinois Extension horticulture educator, Greg Stack. "Rushes are not true grasses, but they look grassy."

Close to 300 species of rush are found throughout the world. Most are native to wet or moist sites in fresh or salt water. Although they are usually found along streams, in marshy areas, or in shallow water, some can tolerate seasonal drought. Rushes can be found in sun or shade, but they grow best in light shade.

They usually have smooth cylindrical leaves. Some are evergreen while others become dormant with the first frost.

Ranging in color from various shades of green through blue-gray, rushes can be as small as six inches tall or giants growing to 6 feet tall. In the garden, rushes are at their best in or near water, particularly alongside ponds. They also grow easily in tubs.

"Some have attractive flowers and foliage that is useful in fresh or dried arrangements," said Stack.

Lately, rushes have caught the interest of growers, who are now offering many new cultivars to gardeners. These new cultivars vary in hardiness. Some are perennials, and some should be treated as annuals.

Among the traditional upright rushes, 'Blue Dart' has blue-green leaves, a strong vertical habit, and grows to be 16 inches tall. It can be used as an alternative to the 'spike,' or dracaena, used in container plantings. It is well suited to many growing conditions, from standing water to dry soils, and is hardy to zone 5.

'Blue Arrows' is a blue-green, upright rush growing to 36 inches tall. It is heat-tolerant and is quite drought-tolerant when grown in the garden. It is also hardy to zone 5 and semi-evergreen over the winter.

The 'Javelin' rush grows to 4 feet tall. It has green leaves and a very rugged, upright habit. It can be grown in standing water, but it also tolerates heat and drought. 'Javelin' is hardy to zone 7 but will still look interesting if left standing in the garden in winter.

Stack suggests planting some 'show-off' rushes to make the garden more interesting.

One of these is 'Spiralis,' also called the corkscrew rush, which has dark green, wire-like foliage that grows in a tight tangle of spirals, much like Shirley Temple's curls. This plant is a real attention-grabber. It prefers very moist to wet conditions, making it a great pond or bog plant. It could also be successfully grown in containers that are placed in shallow bird baths. 'Spiralis' grows to 12 to 14 inches and is hardy to zone 5.

'Frenzy,' or variegated corkscrew rush, also has eye-catching, coiled green leaves, but it goes the extra step by having a bright gold stripe down each of the leaves. 'Big Twister' is another corkscrew rush and sports very upright, bold, spiral leaves. It is an architecturally bold plant, hardy to zone 5, that grows to 24 to 30 inches tall.

'Sword Leaf Rush,' also known by its common name 'Flying Hedgehogs,' is a small North American native that grows to 6 inches tall with flat leaves that resemble dwarf iris. This rush produces round, almost black, spiny seed heads that rise above the foliage and appear to be flying. It prefers moist to wet conditions and is hardy to zone 3.

'Soft Rush,' or common rush, is a clumping plant that grows vertically to about 3 to 4 feet. The medium-green foliage turns a yellow-brown in the fall. Soft rush grows in shallow water or moist, boggy soil and is suitable for pots or tubs. The tall arching stems sway in the breeze and also look very dramatic when back-lit at night.

In conclusion, if you want to do something different and you have a moist to wet spot that is lightly shaded, consider planting a rush.

Source: Greg Stack, Extension Educator, Horticulture, gstack@illinois.edu

Pull date: July 15, 2012