Conditional — Some Areas
Surinam grass (zones 10-13) reaches only part of Arizona (5b-10b): zone 10 are in range, so where you are in the state decides it.
Surinam Grass in Arizona — the short answer
Surinam Grass in Arizona: hardy in zones 10–13, full sun, against a state median of ~266 frost-free days.
- Plant zones
- 10-13
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Arizona zones
- 5b-10b
- USDA PHZM 2023
- Frost window
- Feb 1 - Apr 2 – Nov 13 - Dec 12
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 150 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 90 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Arizona spans zones 5b-10b, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score surinam grass against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Arizona is not one climate
A single Arizona answer averages 15 counties whose growing seasons are 195 days apart — from 150 frost-free days in Coconino County to 345 in Maricopa County. Which end of that your land sits nearer changes what surinam grass can finish before the first hard freeze.
The middle half of 15 counties runs 207–316 days, with a median of 266 days — a 195-day span end to end.
Measured across 15 Arizona counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where Surinam Grass Stands in Arizona
Surinam Grass is rated for zones 10–13 — a cold floor USDA puts at 30 to 40°F. No Arizona county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Arizona winters, not about surinam grass.
Below the zone 10 floor
15 counties
- Coconino County · zone 6a
- Apache County · zone 6b
- Navajo County · zone 7a
3 of 15 shown
Winter cold is the limit here — the same plant works in a container that comes under cover.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.
Zone Comparison
Surinam Grass Needs
- USDA Zones: 10-13
- Frost-Free Days: 90+
- Sun: Full Sun
- Mature size: 2 ft tall
- Drought tolerance: Medium
Arizona Has
- USDA Zones: 5b-10b
- Last Hard Freeze (28°F): Feb 1 - Apr 2
- First Hard Freeze (28°F): Nov 13 - Dec 12
- Annual Rainfall: 3-25 inches
- Common Soils: Caliche, Sandy loam, Desert pavement
Plant Zone Range (zones 10-13)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Surinam Grass in Arizona
The frost window
Across Arizona, the last spring hard freeze (28°F) clears between Feb 1 and Apr 2, and the first fall hard freeze lands between Nov 13 and Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 225-day window you can count on — up to 314 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
When to start the seed
Surinam Grass is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Arizona's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 90 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 135 days to spare even in Arizona's tightest freeze scenario — room for a later start or a second sowing.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says surinam grass survives winter in part of Arizona, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Surinam Grass wants 90+ frost-free days; a typical Arizona site sees ~266 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Surinam Grass needs ~3000 GDD (base 50°F) to ripen. The state median runs ~3945 GDD (from PRISM 1991-2020 climate normals), so Arizona's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Surinam Grass likes near-neutral soil (pH 4.5-6.5). That's the common-ground band across Arizona's caliche and sandy loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5 and 6 — worth knowing before you decide whether a Arizona soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Arizona site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Arizona soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Surinam Grass in Arizona
Zone compatibility tells you about winter cold survival — but Arizona growers also need to think about:
Extreme heat exceeding 110F stresses most plants
Minimal rainfall requires drip irrigation
Caliche hardpan prevents root penetration without breaking through
What to actually do about these — and the constraints that apply to every Arizona grower, not just surinam grass — is covered on the Arizona growing guide.
Timing shifts within Arizona
Surinam Grass needs about 90 days of frost-free season to complete its cycle. Even Coconino County — Arizona’s shortest season at 150 frost-free days — clears that by 60 days, so season length isn’t the constraint anywhere in Arizona. What varies is your own parcel.
Across Arizona’s 15 counties the frost-free season runs from 150 days in Coconino County to 345 days in Maricopa County — a spread of 195 days, which is why a single statewide planting date misleads. The median Arizona county sees 266 frost-free days, leaving surinam grass about 176 days of slack on a typical parcel — room for a second sowing where the season runs long.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Surinam Grass's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Arizona Cooperative Extension
For Arizona-specific cultivar recommendations, planting calendars, and pest pressure for surinam grass, the canonical source is University of Arizona Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Surinam Grass in Arizona
When can I plant Surinam Grass in Arizona?
Arizona's last spring hard freeze (28°F) clears between Feb 1 and Apr 2, and the first fall hard freeze lands between Nov 13 and Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Surinam Grass mature before first frost in Arizona?
Yes — Surinam Grass matures in 90 days (Growable Ground Plant Database), and Arizona's dependable hard-freeze-free window runs 225 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 135 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Surinam Grass grown in across Arizona?
Arizona spans USDA hardiness zones 5b-10b (USDA ARS PHZM 2023). Surinam Grass carries a range of zones 10-13, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Arizona site have?
A typical Arizona site sees ~266 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Surinam Grass needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
How should I amend the soil for Surinam Grass in Arizona?
Surinam Grass prefers pH 4.5-6.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Arizona soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Surinam Grass actually grow on my specific land in Arizona?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores surinam 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 Arizona
State-level data is a sketch. Your Growable Ground report scores surinam grass against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Arizona surinam grass averages can't show:
We read public map data around Arizona — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Arizona surinam grass average
Explore More
Growing guides for surinam grass
Last updated: