Conditional — Some Areas
allium (zones 4-8) reaches only part of Louisiana (8b-10b): zone 8 are in range, so where you are in the state decides it.
Allium in Louisiana — the short answer
Allium in Louisiana: hardy in zones 4–8, full sun, against a state median of ~298 frost-free days.
- Plant zones
- 4-8
- 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
- Louisiana zones
- 8b-10b
- USDA PHZM 2023
- Frost window
- Jan 30 - Feb 17 – Nov 30 - Dec 8
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 265 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
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.
Louisiana spans zones 8b-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 allium 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.
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Louisiana is not one climate
A single Louisiana answer averages 64 counties whose growing seasons are 100 days apart — from 265 frost-free days in Claiborne County to 365 in Plaquemines County. Which end of that your land sits nearer changes what allium can finish before the first hard freeze.
The middle half of 64 counties runs 285–313 days, with a median of 298 days — a 100-day span end to end.
Measured across 64 Louisiana 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 Allium Stands in Louisiana
Allium is rated for zones 4–8 — a cold floor USDA puts at -30 to -20°F. No Louisiana 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 Louisiana winters, not about allium.
Above the zone 8 ceiling
64 counties
- Bienville County · zone 8b
- Bossier County · zone 8b
- Caddo County · zone 8b
3 of 64 shown
Too little winter chill rather than too much cold — a low-chill selection is what changes it.
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
Allium Needs
- USDA Zones: 4-8
- Frost-Free Days: 120+
- Sun: Full Sun
- Mature size: 3 ft tall
- Picking window: ~21 days of harvest
- Drought tolerance: Medium
Louisiana Has
- USDA Zones: 8b-10b
- Last Hard Freeze (28°F): Jan 30 - Feb 17
- First Hard Freeze (28°F): Nov 30 - Dec 8
- Annual Rainfall: 50-65 inches
- Common Soils: Alluvial clay, Muck, Sandy loam
Plant Zone Range (zones 4-8)
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 Allium in Louisiana
The frost window
Across Louisiana, the last spring hard freeze (28°F) clears between Jan 30 and Feb 17, and the first fall hard freeze lands between Nov 30 and Dec 8 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 286-day window you can count on — up to 312 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.
Frost hardiness
Allium takes cold down to about 23°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of Louisiana's window — even a few weeks before the final hard freeze. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
Timing tuned to sub-state frost dates — Claiborne County, not the statewide average.
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 allium survives winter in part of Louisiana, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Allium wants 120+ frost-free days; a typical Louisiana site sees ~298 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
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
Allium tolerates a wide pH range (pH 4.5-7.5) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Louisiana. 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 6 and 6.5 — worth knowing before you decide whether a Louisiana soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Louisiana site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 45.5% of Louisiana as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Allium sits mid-range for drought tolerance, so either extreme can cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
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. Louisiana soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Allium in Louisiana
Zone compatibility tells you about winter cold survival — but Louisiana growers also need to think about:
Extreme humidity and rainfall promote rot and fungal diseases
Poor drainage in delta and coastal areas
Hurricane damage risk from June through November
Growing allium here specifically
Allium needs sharp drainage and sends medium roots; its growing tissue takes cold to about 23°F (FAO ECOCROP), but in Louisiana, about 45.5% of soils are poorly-drained (SSURGO), and standing water is what actually kills it.
Build allium up on a coarse, free-draining mound so its roots never sit in saturated soil. How to handle it →
What to actually do about these — and the constraints that apply to every Louisiana grower, not just allium — is covered on the Louisiana growing guide.
Timing shifts within Louisiana
Louisiana isn't one climate. In Claiborne County, the last hard freeze (28°F) holds until about Mar 2 — roughly 19 days later than the recorded state median — so plant allium to your county's window, not the statewide date.
Allium needs about 120 days of frost-free season to complete its cycle. Even Claiborne County — Louisiana’s shortest season at 265 frost-free days — clears that by 145 days, so season length isn’t the constraint anywhere in Louisiana. What varies is your own parcel.
Across Louisiana’s 64 counties the frost-free season runs from 265 days in Claiborne County to 365 days in Plaquemines County — a spread of 100 days, which is why a single statewide planting date misleads. The median Louisiana county sees 298 frost-free days, leaving allium about 178 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"). Allium's 120-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
Allium draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, allium can only work that bloom inside Louisiana's frost window — roughly 298 days, opening after the last 28°F freeze (Jan 30 - Feb 17) and closing at the first (Nov 30 - Dec 8), per NOAA Regional Climate Centers ACIS, 1991-2020. Deer pressure is meaningful across much of Louisiana; allium is listed as deer-resistant (USDA PLANTS Database), which makes it a safer pick for unfenced sites. Our deer & wildlife guide carries the full deer-resistant list and how to protect the rest.
Good to Know Before You Plant Allium
Allium is listed as toxic to dogs, cats (all) at a moderate level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Louisiana this is a one-season plant and the first hard freeze (Nov 30 - Dec 8) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Allium Varieties for Louisiana
Louisiana publishes no state variety trial for allium, so we won't invent a "best for Louisiana" list. Choose types rated to your USDA hardiness zone (8b-10b), and confirm winter survival and drainage against your own parcel.
Louisiana Cooperative Extension
For Louisiana-specific cultivar recommendations, planting calendars, and pest pressure for allium, the canonical source is LSU AgCenter. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Allium in Louisiana
When can I plant Allium in Louisiana?
Louisiana's last spring hard freeze (28°F) clears between Jan 30 and Feb 17, and the first fall hard freeze lands between Nov 30 and Dec 8 (NOAA Regional Climate Centers ACIS, 1991-2020). Allium takes cold to about 23°F before a freeze kills it (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor), so plant on the early side of that window — even ahead of the final hard freeze.
What hardiness zone is Allium grown in across Louisiana?
Louisiana spans USDA hardiness zones 8b-10b (USDA ARS PHZM 2023). Allium carries a range of zones 4-8, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Louisiana site have?
A typical Louisiana site sees ~298 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Allium needs 120+ 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 Claiborne, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Allium in Louisiana?
Allium tolerates pH 4.5-7.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Louisiana site — amend for drainage and organic matter first.
Will Allium actually grow on my specific land in Louisiana?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores allium 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 Louisiana
State-level data is a sketch. Your Growable Ground report scores allium against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Louisiana allium averages can't show:
We read public map data around Louisiana — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Louisiana allium average
Explore More
Growing guides for allium
Explore Louisiana county by county
Louisiana carries 64 counties with their own USDA zone — a sample of the growing pages for allium there:
Where else allium grows
Allium's zone band crosses state lines — these are the states closest to Louisiana in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Louisiana
Louisiana has a growing page for 1,030 plants — a rotating sample of the rest of the shelf.
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 →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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