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Riverbank Wildrye (Elymus riparius Wiegand)

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Riverbank Wildrye
Photo © Henry Frye, Public Domain.


A perennial, cool-season bunchgrass native mostly to northeastern North America, typically found in riparian areas.

Range - Expand

Native or Not Present
Introduced or Not Present

This tentative map is based on our own research. It may have limited data on Canada and/or Mexico, and there is some subjectivity in our assignment of plants as introduced vs. expanded. Read more in this blog post.

Similar Plants

thumbnail of Canada Wildrye
Canada Wildrye (Elymus canadensis)
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thumbnail of Early Wildrye
Early Wildrye (Elymus macgregorii)
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thumbnail of Silky Wild Rye
Silky Wild Rye (Elymus villosus)
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Found primarily in riparian areas, including floodplain forests, clearings, and grasslands such as meadows and prairies, usually along larger streams, where it grows right up to the water's edge, and sometimes ventures farther from the stream in broad, flat floodplains and swamps adjacent to streams or rivers. Occasionally found in ditches and wet depressions in upland areas, and in sheltered coves in rich montane forests in the Appalachians.

Usually found in moist conditions, but ranges into mesic conditions in shade. Most often found in partial to light shade, with an open canopy letting through some light, but also ranges into full sun on moist sites. Tolerates a range of soil textures including clay-loam, loam, silt, and sand, and even some soils with rocky or gravely material, but seems to prefer alluvial soils, which tend to be porous and nutrient-rich.

Common and abundant in the portion of its range from northeast Ohio through Pennsylvania and New York State into southern New England, but becomes more scattered to uncommon in the Midwest and scattered and rare in the southeastern coastal plain.

Compared to other native Elymus species, this one prefers the wettest conditions, but is the least drought-tolerant. Its shade tolerance is intermediate, considerably less than eastern bottlebrush grass (Elymus hystrix) but more than canada wildrye (Elymus canadensis). It often occurs together with Virginia wildrye (Elymus virginicus).

Life Cycle

This species is a cool-season perennial bunchgrass that flowers later in the season than most other members of its genus.

We found some sources saying that this species is short-lived, but we have also observed individual plants living over 7 years. We have not found any reliable sources establishing its lifespan.

Faunal Associations

We unfortunately could not find any information on relationships between this species specifically. Native Elymus species however tend to support a large number of insect herbivores.


This species is occasionally used for erosion control within its range, and is excellent for this purpose. It is often mixed with Virginia wildrye (Elymus virginicus), which ranges into more mesic moisture conditions.

The exact taxonomic relationships in Elymus are poorly understood and it is not known which species in this genus this one is closest related to.

Riverbank wildrye is more reproductively isolated from other members of the Elymus genus than most are with each other. It has been recorded hybridizing with Virginia wildrye (Elymus virginicus) var. virginicus, and with eastern bottlebrush grass (Elymus hystrix), but the hybrids are usually sterile, often not even producing any seed spikes.


This is one of the many species negatively affected by the invasive plant lesser celandine (Ranunculus ficaria), which tends to dominate in the riparian habitats where this plant grows. Because that plant emerges earlier and this species does not form a long-term seed bank, the competition tends to inhibit seed germination, and often the seeds end up perishing because the competing foliage persists past the time window optimal for this species to germinate and establish. Removal of lesser celandine tends to benefit this species.

Elymus riparius (Riverbank Wild Rye) | Illinois Wildflowers (About This Site)

Elymus riparius (riverbank wildrye) | USDA PLANTS Database (About This Site)

Elymus riparius | Go Botany (About This Site)

River Wild Rye | iNaturalist (About This Site)

Elymus riparius | Biota of North America Project (BONAP) (About This Site)

Elymus riparius | NatureServe Explorer (About This Site)

Elymus riparius | Flora of North America (About This Site)

Riverbank Wildrye | Maryland Biodiversity Project (About This Site)

Photo gallery

Photo © Bonnie Isaac, Public Domain.
Photo © Henry Frye, Public Domain.
Photo © Reuven Martin, Public Domain.
Photo © Owen Strickland, Public Domain.
Photo © Zihao Wang, CC BY 4.0.
Photo © mjpapay, CC BY 4.0.
Photo © Quinten Wiegersma, CC BY 4.0.
Photo © mjpapay, CC BY 4.0.
Photo © Zihao Wang, CC BY 4.0.