San Francisco Bluegrass: A Rare Pacific Northwest Native Worth Knowing
If you’re passionate about native plants and love discovering botanical treasures, San Francisco bluegrass (Poa unilateralis pachypholis) might just pique your interest. This perennial grass represents one of nature’s more elusive characters—a native species that calls the Pacific Northwest home but remains relatively unknown to most gardeners.
What Exactly Is San Francisco Bluegrass?
San Francisco bluegrass belongs to the large Poaceae family, making it a true grass rather than a grass-like impostor. As a perennial, it’s built to stick around year after year, developing robust root systems that help it weather the seasons. You might also encounter it listed under its synonym, Poa pachypholis Piper, in older botanical references.
Where Does It Call Home?
This native grass has a pretty specific address: it’s found naturally in Oregon and Washington, making it a true child of the Pacific Northwest. As a species native to the lower 48 states, it has deep roots in North American ecosystems—literally and figuratively.
The Challenge of Growing San Francisco Bluegrass
Here’s where things get interesting (and a bit tricky). San Francisco bluegrass falls into that category of native plants that are so specialized or rare that detailed growing information is scarce. This isn’t necessarily because it’s difficult to grow—it’s more likely because it’s not commonly available in the nursery trade and hasn’t been extensively studied for garden use.
Should You Try Growing It?
The honest answer? It depends on your gardening goals and access to plant material. Here are some considerations:
- For the native plant purist: If you’re in Oregon or Washington and passionate about growing only plants native to your exact region, this grass could be a Holy Grail find
- For the practical gardener: You might be better served by more readily available native grasses like Oregon bentgrass or other Poa species with known growing requirements
- For restoration projects: This could be valuable if you’re working on habitat restoration in its native range
What We Know (And Don’t Know) About Growing It
Given its Pacific Northwest origins, we can make some educated guesses about San Francisco bluegrass’s preferences. Most grasses from this region appreciate:
- Moderate moisture levels (not too wet, not too dry)
- Well-draining soil
- Cool, mild temperatures
- Some protection from intense summer heat
However, without specific cultivation studies, details about optimal soil pH, fertilization needs, maintenance requirements, and hardiness zones remain unclear.
The Bottom Line
San Francisco bluegrass represents the fascinating world of specialized native plants that exist somewhat under the radar. While it might not be the easiest grass to source or grow, it serves as a reminder of the incredible diversity hidden within our native plant communities.
If you’re determined to grow this particular grass, your best bet is to connect with native plant societies in Oregon and Washington, specialized native seed companies, or botanical gardens that might have experience with rare Pacific Northwest grasses. Just remember—sometimes the journey to find and grow an unusual native plant is half the fun!
For most gardeners looking to add native grasses to their Pacific Northwest landscapes, consider starting with more accessible options like blue wildrye, red fescue, or other well-documented native grasses. You’ll still be supporting native ecosystems while working with plants that have proven track records in cultivation.
