North America Non-native Plant

Spreading Bluegrass

Botanical name: Poa pratensis irrigata

USDA symbol: POPRI2

Life cycle: perennial

Habit: grass

Native status: Non-native, reproduces and persists in the wild in Alaska âš˜ It's either native or not native in Canada âš˜ Non-native, reproduces and persists in the wild in Greenland  

Synonyms: Poa pratensis L. ssp. rigens (Hartm.) Tzvelev (POPRR)  âš˜  Poa pratensis L. var. rigens (Hartm.) Wahlenb. (POPRR2)  âš˜  Poa pratensis L. ssp. subcaerulea (Sm.) Hiitonen (POPRS)  âš˜  Poa subcaerulea Sm. (POSU)   

Spreading Bluegrass: A Northern Grass Worth Considering If you’re gardening in the cooler regions of North America and looking for a hardy perennial grass, you might have come across spreading bluegrass (Poa pratensis irrigata). This resilient graminoid has quietly established itself across several northern territories, from Alaska to Newfoundland, making ...

Spreading Bluegrass: A Northern Grass Worth Considering

If you’re gardening in the cooler regions of North America and looking for a hardy perennial grass, you might have come across spreading bluegrass (Poa pratensis irrigata). This resilient graminoid has quietly established itself across several northern territories, from Alaska to Newfoundland, making it a grass that’s adapted to some pretty challenging climates.

What Exactly Is Spreading Bluegrass?

Spreading bluegrass is a perennial grass that belongs to the broader bluegrass family. While it shares the Poa pratensis name with the more familiar Kentucky bluegrass, this particular variety (irrigata) has its own unique characteristics. You might also see it listed under several scientific synonyms in botanical references, but don’t let that confuse you – it’s all the same hardy northern grass.

Where Does It Grow?

This grass has made itself at home across a impressive swath of northern North America. You’ll find spreading bluegrass growing in:

  • Alberta and British Columbia
  • Alaska
  • Ontario and Quebec
  • Labrador and Newfoundland

Interestingly, while it’s considered non-native in Alaska and Greenland, its status in Canada is less clearly defined. This suggests it may have a complex relationship with the northern landscape – perhaps naturalized in some areas while being truly native in others.

Should You Plant It in Your Garden?

Here’s where things get a bit nuanced. Spreading bluegrass isn’t native to all areas where it now grows, but it’s also not flagged as invasive or noxious. This puts it in that middle ground where it’s not necessarily harmful, but it’s not necessarily the most ecologically beneficial choice either.

The honest truth is that we don’t have complete information about this grass’s wildlife benefits, invasive potential, or specific growing requirements. What we do know is that it’s a perennial grass that’s proven it can handle tough northern conditions.

Consider Native Alternatives First

Before jumping into planting spreading bluegrass, consider exploring native grass options for your area. Native grasses typically:

  • Support local wildlife and pollinators better
  • Require less maintenance once established
  • Are naturally adapted to your local soil and climate
  • Help preserve regional biodiversity

Check with your local native plant society or extension office to learn about indigenous grasses that might serve your landscaping needs.

If You Do Choose to Plant It

Unfortunately, specific growing information for Poa pratensis irrigata is limited in available resources. However, based on its northern distribution and perennial nature, it likely prefers:

  • Cool, moist conditions
  • Well-draining soil
  • Full sun to partial shade
  • Hardy conditions that can handle frost and snow

Given its presence across such a wide northern range, it’s probably quite cold-hardy, potentially suitable for USDA zones 2-6, though this should be verified with local experts.

The Bottom Line

Spreading bluegrass represents one of those middle-ground plants that isn’t necessarily bad but might not be the best choice for ecologically-minded gardeners. If you’re set on using it, it’s probably fine for non-conservation landscapes. However, you might find greater satisfaction – and provide more environmental benefit – by choosing a native grass species instead.

Before making your final decision, consult with local gardening experts who can provide specific advice for your area and help you identify the best native alternatives for your particular gardening goals.

Spreading 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 pratensis L. - Kentucky bluegrass

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