North America Non-native Plant

Drooping Wildrye

Botanical name: Elymus semicostatus

USDA symbol: ELSE6

Life cycle: perennial

Habit: grass

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Synonyms: Agropyron kuramense Melderis (AGKU2)  ⚘  Agropyron semicostatum Nees ex Steud. (AGSE)  ⚘  Agropyron striatum (Nees ex Steud.) Hook. f. (AGST7)  ⚘  Elymus semicostatum (Nees ex Steud.) Á. Löve, orth. var. (ELSE4)   

Drooping Wildrye: A Lesser-Known Perennial Grass If you’ve stumbled across the name drooping wildrye in your plant research, you’re not alone in wondering what exactly this grass is all about. Elymus semicostatus, as it’s known scientifically, is one of those plants that exists in the botanical world but hasn’t quite ...

Drooping Wildrye: A Lesser-Known Perennial Grass

If you’ve stumbled across the name drooping wildrye in your plant research, you’re not alone in wondering what exactly this grass is all about. Elymus semicostatus, as it’s known scientifically, is one of those plants that exists in the botanical world but hasn’t quite made it into mainstream gardening circles—and there are some good reasons why.

What Is Drooping Wildrye?

Drooping wildrye is a perennial grass that belongs to the large family of grasses and grass-like plants. Despite its common name suggesting it might be native to North America (many wildrye grasses are), this particular species is actually non-native to the United States. It has established itself in a very limited range, appearing in just two states: Georgia and Oregon.

The plant has gone through quite a few name changes over the years, which is pretty typical for grasses that taxonomists are still figuring out. You might see it listed under several scientific synonyms in older references, but Elymus semicostatus appears to be the current accepted name.

Should You Consider Planting Drooping Wildrye?

Here’s where things get a bit tricky. While this grass isn’t listed as invasive or noxious, there’s remarkably little information available about its garden performance, care requirements, or even its basic appearance. This lack of horticultural information suggests it’s not commonly cultivated, which raises a few practical questions for home gardeners.

The Native Alternative Approach

Given the limited information about drooping wildrye and its non-native status, you might want to consider some fantastic native grass alternatives instead. If you’re drawn to wildrye grasses, there are several beautiful native options:

  • Canada wildrye (Elymus canadensis) – excellent for naturalized areas
  • Virginia wildrye (Elymus virginicus) – great for woodland edges
  • Blue wildrye (Elymus glaucus) – stunning blue-green foliage

Growing Conditions and Care

Since specific growing information for drooping wildrye is scarce, any cultivation would be somewhat experimental. Like most perennial grasses, it would likely prefer:

  • Full sun to partial shade
  • Well-draining soil
  • Moderate water requirements once established
  • Annual cutting back in late winter or early spring

However, without documented hardiness zones or specific care requirements, growing this grass would involve quite a bit of guesswork.

Wildlife and Ecological Value

While we don’t have specific data on drooping wildrye’s wildlife benefits, most grasses do provide some value to birds through seeds and nesting materials. However, native grasses typically offer far superior ecological benefits, having co-evolved with local wildlife over thousands of years.

The Bottom Line

Drooping wildrye falls into that interesting category of plants that exist but aren’t particularly well-studied or widely grown. If you’re looking for a grass to add to your landscape, you’ll likely have much better success—and provide more ecological value—by choosing a well-documented native species instead.

Sometimes the most interesting plants are the ones that remind us just how vast and mysterious the plant kingdom really is, even if we decide not to invite them into our gardens.

Drooping Wildrye

Classification

Group

Monocot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Liliopsida - Monocotyledons

Subclass

Commelinidae

Order

Cyperales

Family

Poaceae Barnhart - Grass family

Genus

Elymus L. - wildrye

Species

Elymus semicostatus (Nees ex Steud.) Á. Löve - drooping wildrye

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA