Rushes are evergreen, with a texture similar to a grass. Ever heard the ditty “sedges have edges and rushes are round”? This is describing the round blades/stems of a rush, each pushing directly from the soil with no branching. The small flower/seed heads occur at the tips of the stems.
Use in stormwater planters, rain gardens & bioswales:
Given rushes’ tolerance of wet conditions and Portland’s awareness around sustainable stormwater management, perhaps the most sought after use for rushes in the landscape is in any of the many stormwater features such as bioswales, green streets, rain gardens, and stormwater planters bordering buildings. The main function of these features is to filter and disperse our rain events so that the water ending up in our surface waters and groundwaters is cleaner and less impactful with erosion.
Juncus does this well as a high water user and also, as a many stemmed plant, is adept at slowing water down and allowing sediment pollution to settle out. Juncus are by far the most used plant in the City of Portland’s green streets; however, they should by no means be only used as a monoculture. Juncus grow well with other wet-tolerant plants and look beautiful in mixed ecosystems. In larger municipal or industrial scale constructed wetlands (treating stormwater or wastewater), Juncus play an important phytoremediation role.
Use around Ponds:
Juncus is often a mainstay for planting at pond edges, anywhere from wet wicking soil to a water depth of 6-8”. Planted in clumps and mixed with other native or ornamental pond edge plants, Juncus provides habitat for a variety of birds and frogs and other aquatic life.
Use in Container Plantings:
Juncus are fairly forgiving of a range of soil and moisture conditions, and they have a clumping and spiky architecture that looks great in mixed planters. If you are designing your planter by the “thrillers, fillers, and spillers” mantra, Juncus can be used as either central thrillers (tall vertical elements planted near the center of the pot) or background fillers (medium height space fillers in a ring around the central thriller). See below for descriptions of some of the ornamental varieties commonly available.
Other Cultural Uses:
Juncus stems are frequently used in modern basket weaving traditions around the world- making a variety of baskets, mats, cording, brushes/brooms, sieves, etc. The Latin root of Juncus means “to join, tie, or bind”, in reference to these uses. There are medicinal uses for Juncus species in Eastern systems of healing. And long ago in ancient Egypt, the stiffer Juncus stems were used as writing implements.
Some varieties you can often find at Portland Nursery include:
This species is one of the most common and hybridizes easily. Sometimes also known as ‘field rush’ and is often able to grow in wet meadows or even drier fields.
Juncus effuses ‘Goldstrike’
Juncus effuses ‘Goldstrike’ bears a distinctive gold stripe runs the full length of each stem, accenting the vertical energy. Approximately 18” tall.
Juncus effuses ‘Spiralis’
This variety has tightly coiled/spiraled stems that may uncoil somewhat as they grow, and they tend to grow in all directions to 14-18” tall, looking like wild Medusa hair. This growth habit can look extremely interesting in containers but possibly ‘messier’ in the landscape. Deer resistant. Full sun.
One of the few species permitted in Portland public stormwater systems, perhaps because of its reliably clumping habit.
Juncus patens ‘Elk’s Blue’
A variety with narrower and bluish colored stems, introduced by the California nursery San Marcos Growers. Tightly clumped and growing 18-24” tall. One of the rushes tolerant of dry and/or shady landscapes.
Juncus inflex ‘Blue Arrow’
Another light green or gray blue colored variety. A wispier texture. Can be grown in the typical wet conditions but is also drought-tolerant once established.
Also called pale or giant rush. Strong, thick stems. Sometimes salt-tolerant.
A native wetland species with uncharacteristic flat blades/stems, making it look like a mini iris. Typically only 8-12” tall.
Common Name: Rush
Origin: Juncus are widely naturalized across the world, and specific origins are often confusing. They are considered native to Asia, Europe, Africa, and the Americas and more frequently occurring in temperate (vs tropical) biomes.
Culture: Rushes grow in a wide variety of environments. They will usually look best in consistently moist soils; they tolerate shallow inundation, as with pond edges or stormwater planters (see discussion below), or flowing water, along streams. But many of them also grow well in fields or in mixed container plantings. For the most part, they will prefer sun, though partial shade will be tolerated fairly easily. They also tolerate poor soil qualities.
Maintenance: Rushes need extremely minimal maintenance, and one of the horticultural mistakes often made with them is to prune them too much or to prune them like a grass. Though rushes look like grasses, they cannot be treated the same. They are evergreen and if mowed, they will never look quite as beautiful again.
If rushes experience a dry spell and many of the stems turn brown, the best approach is to meticulously prune out entire dead stems and only dead stems. Most newer growth will occur at the outer edge of the clump. If this should result in a large dead space in the center, the rush can be dug up, divided, and replanted for more aesthetic clump architecture.
Though rushes do spread through rhizomes, they are largely clumping and rarely present enough aggression to bother controlling, in the Pacific Northwest. The small flower/seed heads are quite ornamental and again, are not normally aggressive around here.
Pests and Diseases: Rushes are relatively pest and disease free, and very few animals will seek them out as a preferred food. Even in a pond environment, they seem not to be a favored food of nutria- an animal that will eat almost everything. I would count the weed-whacker or indiscriminate pruner as one of the biggest ‘pest’ dangers to a rush (see maintenance).