Generally — Most Areas
St. Augustine grass (zones 8-10) partially overlaps with Oregon (4b-9b). It can grow in zones 8-9 within the state.
Your yard isn't the whole zone.
Oregon spans zones 4b-9b, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score st augustine grass against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
St Augustine Grass Needs
- USDA Zones: 8-10
- Soil pH: 5 - 8.5
- Sun: Part Sun
- Drainage: well (dry spells)
- Frost-Free Days: 150+
Oregon Has
- USDA Zones: 4b-9b
- Last Frost: Mar 1 - Jun 15
- First Frost: Sep 1 - Nov 15
- Annual Rainfall: 8-90 inches
- Common Soils: Volcanic, Silt loam (Willamette), Sandy loam
Plant Zone Range (zones 8-10)
Preferred Soil pH
Plant data: USDA PLANTS Database / plant_species_v5.csv. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant St Augustine Grass in Oregon
The frost window
Across Oregon, the last spring frost clears between Mar 1 and Jun 15, and the first fall frost lands between Sep 1 and Nov 15 (NOAA Climate Normals 1991-2020). Counting from the latest last frost to the earliest first frost, that's a 78-day window you can count on — up to 259 days on a mild site in a kind year.
Frost tenderness
St Augustine Grass is frost-tender — its listed minimum temperature is 50°F (USDA PLANTS Database) — so set plants out after the last frost has cleared your local site, not the state's earliest date.
Establishment timing
As a long-lived plant, st augustine grass isn't racing the calendar to a harvest date. Plant it in spring once the last-frost window passes so roots settle in through the full season, or in early fall while the soil still holds summer warmth.
Timing tuned to sub-state frost dates — Deschutes County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
Zone compatibility says you can survive winter here. Whether the growing season is long enough — and warm enough — is a different question.
Frost-free days
St Augustine Grass wants 150+ frost-free days; a typical Oregon site sees ~170 (NOAA Climate Normals). That leaves a workable window — start indoors to bank time.
Climate aggregates derive from USDA NRCS county-level hardiness data + Cornell CALS Extension GDD-by-region tables + MSU Extension chill-hours-by-zone (1991-2020 NOAA Climate Normals baseline).
Soil + Drainage Fit
St Augustine Grass likes near-neutral soil (pH 5-8.5). That's the common-ground band across Oregon's volcanic and silt loam (willamette) — a soil test confirms it for your site. Drainage matters: this plant wants well (dry spells). If your Oregon site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Oregon's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel — that map unit, not the state average, decides how st augustine grass performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Oregon soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
St Augustine Grass in Oregon — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 8-10 (USDA PLANTS Database)
- State Zones: 4b-9b (USDA ARS PHZM 2023)
- Growing Season: Mar 1 - Jun 15 to Sep 1 - Nov 15 (NOAA Climate Normals)
What Else to Consider
Zone compatibility tells you about winter cold survival — but Oregon growers also need to think about:
West side: excessive rain and overcast skies reduce sun for warm-season crops
Map your sun honestly — a south-facing bed against a light wall recovers a surprising amount of the light the clouds take.
East side: arid conditions (8-15 inches rainfall) require irrigation
East of the Cascades, drip irrigation is infrastructure, not an accessory — plan it before the first planting.
Slug pressure is extreme in western Oregon
Evening patrols, iron-phosphate baits, and dry mulch edges knock slugs back — your extension guide covers the full toolkit.
Mountain areas have very short seasons (60-90 frost-free days)
At 60-90 frost-free days, season extension is the difference between a garden and a gamble — a high tunnel changes the math.
Growing st augustine grass here specifically
St Augustine Grass wants pH 5.0–8.5 and rates to USDA zones 8–10, but Oregon's soils are dominantly silt loam — the fit is decided by your parcel's own map unit, not the state average.
Match st augustine grass to your parcel's SSURGO map unit — test pH and texture, and amend toward its 5.0–8.5 range. How to handle it →
Timing shifts within Oregon
Oregon isn't one climate. In Deschutes County, the last hard freeze (28°F) holds until about May 5 — roughly 36 days later than the recorded state median — so plant st augustine grass to your county's window, not the statewide date.
County last-freeze dates: NOAA/PRISM Climate Normals 1991-2020, 28°F threshold (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Oregon Cooperative Extension
For Oregon-specific cultivar recommendations, planting calendars, and pest pressure for st augustine grass, the canonical source is OSU Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is St Augustine Grass native to Oregon?
St Augustine Grass is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Oregon. It can still earn a place in a Oregon garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The Oregon growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing St Augustine Grass in Oregon
When can I plant St Augustine Grass in Oregon?
Oregon's last spring frost clears between Mar 1 and Jun 15, and the first fall frost lands between Sep 1 and Nov 15 (NOAA Climate Normals 1991-2020). St Augustine Grass is a long-lived planting, so target spring just after your local last frost — or early fall while the soil holds warmth — and let it establish through the season.
What hardiness zone is St Augustine Grass grown in across Oregon?
Oregon spans USDA hardiness zones 4b-9b (USDA ARS PHZM 2023). St Augustine Grass carries a range of zones 8-10, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Oregon site have?
A typical Oregon site sees ~170 frost-free days per year (derived from NOAA Climate Normals 1991-2020). St Augustine Grass needs 150+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Deschutes, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is St Augustine Grass native to Oregon?
St Augustine Grass is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Oregon. It can still earn a place in a Oregon garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for St Augustine Grass in Oregon?
St Augustine Grass prefers pH 5-8.5 and well (dry spells) drainage (USDA PLANTS Database). That sits in the common-ground band across Oregon soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will St Augustine Grass actually grow on my specific land in Oregon?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores st augustine grass against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Oregon
State-level data is a sketch. Your Growable Ground report scores st augustine grass against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →