Conditional — Some Areas
blue vervain (zones 3-8) reaches only part of Louisiana (8b-10b): zone 8 are in range, so where you are in the state decides it.
Blue Vervain in Louisiana — the short answer
Blue Vervain in Louisiana: hardy in zones 3–8, against a state median of ~298 frost-free days.
- Plant zones
- 3-8
- 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 sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score blue vervain against your parcel's actual hardiness, soil, and sun.
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
Louisiana is not one climate
Louisiana’s winter-low ladder runs across 64 counties, from zone 8.5 in Bienville County to zone 10 in Plaquemines County. That is 15°F between the two counties’ average coldest night — the difference between blue vervain overwintering in the ground and coming under cover.
The middle half of 64 counties runs 8.5–9 zones, with a median of 9 zones — a 1.5-zone span end to end.
Measured across 64 Louisiana 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 Blue Vervain Stands in Louisiana
Blue Vervain is rated for zones 3–8 — a cold floor USDA puts at -40 to -30°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 blue vervain.
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
Blue Vervain Needs
- USDA Zones: 3-8
- Mature size: 5 ft tall
- Picking window: ~45 days of harvest
- Drought tolerance: Low
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 3-8)
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 Blue Vervain 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.
Winter standing
Louisiana runs as cold as USDA zone 8, and no sourced winter-hardiness floor is on record for blue vervain, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether blue vervain is a permanent planting or a replant-every-spring crop for you turns on your own zone within Louisiana; 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.
What Else to Consider for Blue Vervain 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
What to actually do about these — and the constraints that apply to every Louisiana grower, not just blue vervain — is covered on the Louisiana growing guide.
Where in Louisiana Blue Vervain Is Zone-Hardy
Blue Vervain is rated for USDA zones 3–8. Every Louisiana county sits above it. Even Bienville County, the state’s coldest at zone 8b, is milder than the plant’s zone 8 ceiling — the constraint here is winter chill it will not get, not cold it cannot take.
Across those 64 counties Louisiana’s winter-low ladder runs from zone 8b in Bienville County to zone 10a in Plaquemines County — 1.5 USDA zones of spread, which is 15°F between the two counties’ average coldest night of the year. None of that range reaches the band blue vervain needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Blue Vervain’s zone 3–8 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Blue Vervain draws honeybees, native bees, butterflies, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, blue vervain 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.
Louisiana Cooperative Extension
For Louisiana-specific cultivar recommendations, planting calendars, and pest pressure for blue vervain, the canonical source is LSU AgCenter. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Blue Vervain native to Louisiana?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Blue Vervain as native to Louisiana. Planting it supports the pollinators and wildlife that evolved alongside it.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Blue Vervain in Louisiana
When can I plant Blue Vervain 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). No sourced winter-hardiness floor is on record for Blue Vervain, so this page does not state whether it overwinters in Louisiana 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 Blue Vervain grown in across Louisiana?
Louisiana spans USDA hardiness zones 8b-10b (USDA ARS PHZM 2023). Blue Vervain carries a range of zones 3-8, 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). Blue Vervain should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Blue Vervain native to Louisiana?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Blue Vervain as native to Louisiana. Planting it supports the pollinators and wildlife that evolved alongside it.
Will Blue Vervain actually grow on my specific land in Louisiana?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores blue vervain 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 blue vervain against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Louisiana blue vervain 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 blue vervain average
Explore More
Growing guides for blue vervain
Explore Louisiana county by county
Louisiana carries 64 counties with their own USDA zone — a sample of the growing pages for blue vervain there:
Where else blue vervain grows
Blue Vervain'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.
Last updated: