North America Native Plant

Yellow Spikerush

Botanical name: Eleocharis flavescens var. thermalis

USDA symbol: ELFLT

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Synonyms: Eleocharis thermalis Rydb. (ELTH)   

Yellow Spikerush: A Specialized Native Sedge for Western Gardens If you’re looking to add authentic native character to your garden, yellow spikerush (Eleocharis flavescens var. thermalis) might catch your attention. This perennial sedge represents one of nature’s more specialized plants, perfectly adapted to specific environments across the western United States. ...

Rare plant alert!

Region: Conservation status by state

Status: S5T2T3Q: Status is uncertain but is somewhere between the following rankings: Uncertain taxonomy: ⚘ Subspecies or variety is imperiled: Extremely rare due to factor(s) making it especially vulnerable to extinction. Typically 6 to 20 occurrences or few remaining individuals (1,000 to 3,000) ⚘ Subspecies or variety is vulnerable: Either very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or factors are making it vulnerable to extinction. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals. ⚘ Secure: At very low or no risk of extinction in the jurisdiction due to a very extensive range, abundant populations or occurrences, with little to no concern from declines or threats. ⚘

Yellow Spikerush: A Specialized Native Sedge for Western Gardens

If you’re looking to add authentic native character to your garden, yellow spikerush (Eleocharis flavescens var. thermalis) might catch your attention. This perennial sedge represents one of nature’s more specialized plants, perfectly adapted to specific environments across the western United States.

What is Yellow Spikerush?

Yellow spikerush is a grass-like perennial that belongs to the sedge family (Cyperaceae). Don’t let the name fool you—while it looks like grass, it’s actually quite different. This native plant has carved out its own niche in the American West, where it thrives in conditions that would challenge many other plants.

You might also encounter this plant listed under its scientific synonym, Eleocharis thermalis, in older botanical references.

Where Does Yellow Spikerush Call Home?

This native beauty has made itself at home across five western states: Arizona, California, Montana, Utah, and Wyoming. Its distribution tells a story of adaptation to diverse western landscapes, from desert regions to mountain areas.

Should You Plant Yellow Spikerush in Your Garden?

Here’s where things get interesting—and a bit complicated. Yellow spikerush falls into that category of plants that native gardening enthusiasts love to discover, but it comes with some important considerations.

The Good News

  • It’s a true native, supporting local ecosystems
  • As a perennial, it provides year-round structure
  • Adds authentic regional character to western gardens
  • Part of the diverse sedge family that often goes unnoticed but plays important ecological roles

The Reality Check

Unfortunately, specific growing information for this particular variety is quite limited in horticultural sources. This likely reflects its specialized nature and possibly restricted habitat requirements. Additionally, conservation status information suggests this plant may be uncommon in its native range.

Important note: If you do decide to pursue this plant, please ensure you source it responsibly from reputable native plant nurseries that propagate their own stock rather than wild-collecting.

Growing Conditions and Care

While specific cultivation information for yellow spikerush is limited, we can make some educated guesses based on its sedge family characteristics and native habitat:

  • Likely prefers consistently moist to wet conditions
  • May require specialized soil conditions
  • Probably suited to full sun to partial shade
  • Best adapted to western climate conditions

Alternative Considerations

Given the limited availability and growing information for this specific variety, you might consider other native sedges or grass-like plants that are better documented and more readily available for home cultivation. Your local native plant society or extension office can suggest similar natives that would provide comparable ecological benefits with more predictable garden performance.

The Bottom Line

Yellow spikerush represents the fascinating diversity of native plants, but it’s definitely more of a specialist’s plant than a beginner-friendly garden choice. If you’re drawn to native sedges and grass-like plants, start with more commonly available species and work your way up to the rarities like this one.

Remember, the best native garden is one that thrives—and sometimes that means choosing the natives that are most likely to succeed in your specific garden conditions.

Yellow Spikerush

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

Cyperaceae Juss. - Sedge family

Genus

Eleocharis R. Br. - spikerush

Species

Eleocharis flavescens (Poir.) Urb. - yellow spikerush

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