lablab (Lablab purpureus), photographi

Can I Grow Lablab in Arizona?

USDA Zones 5b-10b · Plant zone range 7-13

Generally — Most Areas

lablab (zones 7-13) suits most of Arizona (5b-10b) — zones 7-10 are in range, and the rest of the state is the exception.

Lablab in Arizona — the short answer

Lablab in Arizona: hardy in zones 7–13, full sun, against a state median of ~266 frost-free days.

Plant zones
7-13
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.

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Your yard isn't the whole zone.

Arizona spans zones 5b-10b, 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 lablab against your parcel's actual hardiness, soil, and sun.

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Arizona is not one climate

Arizona’s winter-low ladder runs across 15 counties, from zone 6 in Coconino County to zone 9.5 in Yuma County. That is 35°F between the two counties’ average coldest night — the difference between lablab overwintering in the ground and coming under cover.

6 zonesCoconino County9.5 zonesYuma County

The middle half of 15 counties runs 7.59.5 zones, with a median of 8.5 zones — a 3.5-zone span end to end.

Measured across 15 Arizona counties. USDA PHZM 2023, per county. 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 in Arizona Fits Best

Lablab is rated for zones 713 — a cold floor USDA puts at 0 to 10°F. Against Arizona’s 15 counties that band holds in 13 of them, and the line runs at Navajo County (zone 7a), the coldest county still inside it.

Inside zones 7–13

13 counties

3 of 13 shown

Below the zone 7 floor

2 counties

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.

Even within Arizona's zones 5b-10b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for lablab (USDA PHZM 2023):

Zone Comparison

Lablab Needs

  • USDA Zones: 7-13
  • Frost-Free Days: 70+
  • Sun: Full Sun
  • Mature size: 4 ft tall
  • Drought tolerance: High

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 7-13)

7a
13b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 4.58.0

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 Lablab 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

Lablab 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.

Winter standing

Arizona runs as cold as USDA zone 5, and no sourced winter-hardiness floor is on record for lablab, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether lablab is a permanent planting or a replant-every-spring crop for you turns on your own zone within Arizona; check its hardiness range against that before treating it as long-lived ground.

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 lablab 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

Lablab wants 70+ 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

Lablab needs ~2500 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

Lablab tolerates a wide pH range (pH 4.5-8) — 3.5 units, acid ground through alkaline — so soil acidity is rarely what limits it in Arizona. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5 and 7.5 — 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 Lablab 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 lablab — is covered on the Arizona growing guide.

Timing shifts within Arizona

Lablab needs about 70 days of frost-free season to complete its cycle. Even Coconino County — Arizona’s shortest season at 150 frost-free days — clears that by 80 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 lablab about 196 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"). Lablab's 70-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Pollinator + Wildlife Value

Lablab draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, lablab can only work that bloom inside Arizona's frost window — roughly 266 days, opening after the last 28°F freeze (Feb 1 - Apr 2) and closing at the first (Nov 13 - Dec 12), per NOAA Regional Climate Centers ACIS, 1991-2020.

Arizona Cooperative Extension

For Arizona-specific cultivar recommendations, planting calendars, and pest pressure for lablab, the canonical source is University of Arizona Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Lablab native to Arizona?

No — the USDA PLANTS Database lists Lablab as introduced rather than native in the Lower 48, so it is not part of Arizona's native flora. It grows here as a garden plant; pairing it with a few Arizona natives keeps local pollinators fed too.

Looking for plants that belong here? The Arizona 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 Lablab in Arizona

When can I plant Lablab 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). No sourced winter-hardiness floor is on record for Lablab, so this page does not state whether it overwinters in Arizona and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.

What hardiness zone is Lablab grown in across Arizona?

Arizona spans USDA hardiness zones 5b-10b (USDA ARS PHZM 2023). Lablab carries a range of zones 7-13, 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). Lablab needs 70+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.

Is Lablab native to Arizona?

No — the USDA PLANTS Database lists Lablab as introduced rather than native in the Lower 48, so it is not part of Arizona's native flora. It grows here as a garden plant; pairing it with a few Arizona natives keeps local pollinators fed too.

How should I amend the soil for Lablab in Arizona?

Lablab tolerates pH 4.5-8 and well (dry spells) drainage (FAO ECOCROP). That is a 3.5-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Arizona site — amend for drainage and organic matter first.

Will Lablab actually grow on my specific land in Arizona?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores lablab against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in Arizona

State-level data is a sketch. Your Growable Ground report scores lablab against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that Arizona lablab averages can't show:

Your soil pHYour frost-free days — Arizona averages 266Your sun & shade

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 lablab average

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