Native Plants

Cottongrass

Eriophorum ×rousseauanum

USDA symbol: ERRO4

perennial grass

Alaska: native

If you’re looking for a truly unique addition to your native plant collection, Eriophorum ×rousseauanum might just be the unicorn you’ve been searching for. This rare cottongrass hybrid is as elusive as it is intriguing, representing one of nature’s fascinating botanical experiments in the wilds of Alaska. Eriophorum ×rousseauanum is ...

Cottongrass: Alaska’s Elusive Native Hybrid

If you’re looking for a truly unique addition to your native plant collection, Eriophorum ×rousseauanum might just be the unicorn you’ve been searching for. This rare cottongrass hybrid is as elusive as it is intriguing, representing one of nature’s fascinating botanical experiments in the wilds of Alaska.

What Makes This Cottongrass Special

Eriophorum ×rousseauanum is a perennial hybrid cottongrass that belongs to the sedge family, despite its grass-like appearance. Don’t let the × symbol in its name intimidate you – it simply indicates that this is a natural hybrid between two parent Eriophorum species. You might also encounter it under the synonym Eriophorum ×sorensenii Raymond in some botanical references.

As a graminoid (that’s botanist-speak for grass-like plant), this cottongrass joins the ranks of sedges, rushes, and true grasses that add texture and movement to natural landscapes.

Where Does It Call Home

This cottongrass hybrid is exclusively native to Alaska, making it a true Alaskan endemic. Its distribution appears to be quite limited within the state, which adds to its mystique and rarity in the gardening world.

  • Species observed
  • No observations

The Reality Check: Should You Grow It

Here’s where we need to have an honest conversation. While Eriophorum ×rousseauanum sounds absolutely fascinating on paper, the practical reality is that this plant presents some significant challenges for home gardeners:

  • Extremely limited availability – you’re unlikely to find this at your local nursery
  • Specialized growing requirements that aren’t well documented
  • Adapted to Alaska’s unique climate conditions
  • May require permits or special consideration due to its rarity

Alternative Native Cottongrasses to Consider

If you’re drawn to the idea of growing cottongrass but live outside of Alaska or want something more readily available, consider these alternatives:

  • Look for other Eriophorum species native to your region
  • Explore local sedge species that offer similar aesthetic appeal
  • Consult with native plant societies in your area for suitable substitutes

Growing Conditions (What We Know)

While specific growing information for this hybrid is scarce, cottongrasses in general tend to thrive in:

  • Wetland or bog-like conditions
  • Acidic, nutrient-poor soils
  • Full sun to partial shade
  • Consistently moist to wet conditions
  • Cold climate zones

The Bottom Line

Eriophorum ×rousseauanum represents the fascinating world of rare native plants that exist primarily in their natural habitats. While we can appreciate and study these botanical treasures, they’re often best left to flourish in the wild landscapes they’ve called home for generations.

If you’re passionate about supporting native plant diversity, consider focusing on more readily available native species in your area, or support conservation efforts that protect the natural habitats where rare hybrids like this cottongrass continue to thrive.

Eriophorum ×rousseauanum is also known as...

Often we refer to plants by their common names. When shopping for plants the scientific name is the best way to positively identify the plant species you desire. But some plants have more than one name! While it doesn't happen often, nurseries might display one name while you're searching for another. Eriophorum ×rousseauanum is also known as:

Eriophorum ×sorensenii | USDA symbol: ERSO

Why do some plants have more than one name? Over time plant species may be renamed for a few reasons:

  1. Botanists in different regions named the same plant without knowing it had already been classified.
  2. A species was reclassified after scientific advances in, for example, DNA analysis.
  3. Slight variations within a species are sometimes mistakenly identified as entirely new species.

Classification

Group: Monocot
Kingdom: Plantae - Plants
Subkingdom: Tracheobionta - Vascular plants
Superdivision: Spermatophyta - Seed plants
Division: Magnoliophyta - Flowering plants
Class: Liliopsida - Monocotyledons
Subclass: Commelinidae
Order: Cyperales
Family: Cyperaceae Juss. - Sedge family
Genus: Eriophorum L. - cottongrass

Species: Eriophorum ×rousseauanum Raymond [angustifolium × scheuchzeri] - cottongrass

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