North America Native Plant

Rhizome Bluegrass

Botanical name: Poa rhizomata

USDA symbol: PORH

Life cycle: perennial

Habit: grass

Native status: Native to the lower 48 states  

Rhizome Bluegrass: A Pacific Coast Native Worth Discovering If you’re gardening along the Pacific Coast and looking for a native grass that’s both beautiful and functional, rhizome bluegrass (Poa rhizomata) might just be the hidden gem you’ve been searching for. This perennial grass offers a unique combination of coastal charm ...

Rare plant alert!

Region: Conservation status by state

Status: S3S4: Status is uncertain but is somewhere between the following rankings: 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 ⚘ Apparently Secure: Uncommon but not rare, and usually widespread. Possibly cause for longterm concern. Typically more than 100 occurrences in the state or more than 10,000 individuals ⚘

Rhizome Bluegrass: A Pacific Coast Native Worth Discovering

If you’re gardening along the Pacific Coast and looking for a native grass that’s both beautiful and functional, rhizome bluegrass (Poa rhizomata) might just be the hidden gem you’ve been searching for. This perennial grass offers a unique combination of coastal charm and practical landscaping benefits that make it a standout choice for the right garden setting.

What Makes Rhizome Bluegrass Special?

Rhizome bluegrass is a true Pacific Coast native, naturally occurring in California and Oregon. As its name suggests, this grass spreads through underground rhizomes, creating dense, low-growing mats of fine-textured, blue-green foliage. The result is a naturally beautiful ground cover that looks equally at home in a formal landscape design or a wild, naturalized setting.

This perennial grass belongs to the graminoid family, which includes various grass-like plants. What sets rhizome bluegrass apart from many other grasses is its ability to form cohesive patches while maintaining an attractive, refined appearance throughout the growing season.

Where Does It Grow?

Rhizome bluegrass has a relatively limited native range, growing naturally in coastal areas of California and Oregon. This makes it particularly valuable for gardeners in these regions who want to create authentic native landscapes.

A Word About Conservation

Before you rush out to plant rhizome bluegrass, there’s something important to know: this species has a Global Conservation Status of S3S4, indicating it’s somewhat uncommon in its native range. This doesn’t mean you shouldn’t grow it – quite the opposite! Growing native plants like rhizome bluegrass can actually help support local biodiversity. However, it does mean you should be thoughtful about sourcing your plants.

Always purchase rhizome bluegrass from reputable native plant nurseries that propagate their plants responsibly rather than collecting from wild populations. This ensures you’re supporting conservation efforts rather than potentially harming wild stands of this special grass.

Is Rhizome Bluegrass Right for Your Garden?

Rhizome bluegrass shines in specific garden situations:

  • Native gardens: Perfect for authentic Pacific Coast native plant landscapes
  • Coastal properties: Naturally adapted to coastal growing conditions
  • Erosion control: The rhizomatous growth habit makes it excellent for stabilizing slopes
  • Ground cover areas: Creates attractive, low-maintenance coverage in appropriate zones
  • Restoration projects: Valuable for habitat restoration in its native range

Growing Conditions and Care

If you’re gardening in USDA hardiness zones 8-10 along the Pacific Coast, rhizome bluegrass could be an excellent addition to your landscape. Here’s what this coastal native needs to thrive:

Sun and Shade: Rhizome bluegrass adapts well to various light conditions, from partial shade to full sun, making it quite versatile for different garden spots.

Soil Preferences: Well-draining soils are essential. This grass has evolved in coastal conditions and doesn’t appreciate soggy, waterlogged situations.

Water Needs: Once established, rhizome bluegrass is quite drought tolerant – a valuable trait for water-wise gardening. During establishment, provide regular water, but mature plants can handle dry periods typical of their native coastal environment.

Planting and Maintenance Tips

Getting rhizome bluegrass established successfully is straightforward if you follow these guidelines:

  • Plant in fall or early spring for best establishment
  • Space plants appropriately to allow for natural spreading
  • Water regularly during the first growing season
  • Once established, maintenance is minimal
  • Allow the grass to spread naturally to form attractive colonies

Wildlife and Ecosystem Benefits

While rhizome bluegrass is wind-pollinated and doesn’t offer direct nectar benefits to pollinators, it still plays important ecological roles. Native grasses like this one provide habitat structure for small wildlife, contribute to the overall biodiversity of native plant communities, and help create authentic coastal ecosystems in garden settings.

The dense growth habit also makes it valuable for soil stability and erosion control, particularly important in coastal environments where wind and weather can be challenging.

The Bottom Line

Rhizome bluegrass deserves serious consideration if you’re gardening within its native range along the Pacific Coast. Its combination of attractive appearance, practical benefits, and native status makes it a valuable addition to the right garden. Just remember to source your plants responsibly to support conservation efforts, and ensure your growing conditions match this coastal native’s preferences.

For gardeners outside its native range, consider exploring other native grasses that are naturally suited to your specific region – there’s likely a local native that can provide similar benefits while supporting your area’s unique ecosystem.

Rhizome Bluegrass

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

Poa L. - bluegrass

Species

Poa rhizomata Hitchc. - rhizome bluegrass

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