Yes — Strong Match
blue lobelia (zones 4-9) covers every zone Tennessee contains (6a-8a), so hardiness is not what limits it anywhere in the state.
Your yard isn't the whole zone.
Tennessee spans zones 6a-8a, 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 lobelia against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Blue Lobelia Needs
- USDA Zones: 4-9
- Mature size: 3 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Low
Tennessee Has
- USDA Zones: 6a-8a
- Last Hard Freeze (28°F): Mar 21 - Mar 29
- First Hard Freeze (28°F): Nov 5 - Nov 12
- Annual Rainfall: 45-55 inches
- Common Soils: Silt loam, Clay loam, Limestone-derived
Plant Zone Range (zones 4-9)
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Blue Lobelia in Tennessee
The frost window
Across Tennessee, the last spring hard freeze (28°F) clears between Mar 21 and Mar 29, and the first fall hard freeze lands between Nov 5 and Nov 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 221-day window you can count on — up to 236 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
Tennessee runs as cold as USDA zone 6, and no sourced winter-hardiness floor is on record for blue lobelia, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether blue lobelia is a permanent planting or a replant-every-spring crop for you turns on your own zone within Tennessee; check its hardiness range against that before treating it as long-lived ground.
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.
Blue Lobelia in Tennessee — Quick Answer
- Verdict: Yes — Strong Match
- Plant Zones: 4-9 (USDA PLANTS Database)
- State Zones: 6a-8a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Mar 21 - Mar 29 to Nov 5 - Nov 12 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Blue Lobelia in Tennessee
Zone compatibility tells you about winter cold survival — but Tennessee growers also need to think about:
Heavy clay soils in the Nashville Basin
High humidity promotes disease in summer
Variable spring weather with late frost risk
What to actually do about these — and the constraints that apply to every Tennessee grower, not just blue lobelia — is covered on the Tennessee growing guide.
Where in Tennessee Blue Lobelia Is Zone-Hardy
Blue Lobelia is rated for USDA zones 4–9. Every one of Tennessee’s 95 counties sits inside that band — from Carter County at zone 7a to Tipton County at zone 8a — so winter cold is not what decides this plant anywhere in the state. What is left to vary is your own parcel: slope, shelter and cold-air drainage routinely move a site half a zone either way from the county figure.
Across those 95 counties Tennessee’s winter-low ladder runs from zone 7a in Carter County to zone 8a in Tipton County — 1 USDA zone of spread, which is 10°F between the two counties’ average coldest night of the year. That is why a statewide hardiness answer is where you start and not where you finish.
The planting window moves with it. Johnson County holds its last hard freeze (28°F) until about Apr 14, while Shelby County is clear by Mar 4 — 41 days apart. Set blue lobelia out on your county’s date, not the state’s.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F killing freeze — earlier than the folk 32°F "last frost". Blue Lobelia’s zone 4–9 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Where in Tennessee Fits Best
Even within Tennessee's zones 6a-8a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for blue lobelia (USDA PHZM 2023):
Pollinator + Wildlife Value
Blue Lobelia draws 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 lobelia can only work that bloom inside Tennessee's frost window — roughly 230 days, opening after the last 28°F freeze (Mar 21 - Mar 29) and closing at the first (Nov 5 - Nov 12), per NOAA Regional Climate Centers ACIS, 1991-2020.
Tennessee Cooperative Extension
For Tennessee-specific cultivar recommendations, planting calendars, and pest pressure for blue lobelia, the canonical source is UT Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Blue Lobelia native to Tennessee?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Blue Lobelia as native to Tennessee. 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 Lobelia in Tennessee
When can I plant Blue Lobelia in Tennessee?
Tennessee's last spring hard freeze (28°F) clears between Mar 21 and Mar 29, and the first fall hard freeze lands between Nov 5 and Nov 12 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Blue Lobelia, so this page does not state whether it overwinters in Tennessee 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 Lobelia grown in across Tennessee?
Tennessee spans USDA hardiness zones 6a-8a (USDA ARS PHZM 2023). Blue Lobelia carries a range of zones 4-9, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Tennessee site have?
A typical Tennessee site sees ~230 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Blue Lobelia 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 Lobelia native to Tennessee?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Blue Lobelia as native to Tennessee. Planting it supports the pollinators and wildlife that evolved alongside it.
Will Blue Lobelia actually grow on my specific land in Tennessee?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores blue lobelia 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 Tennessee
State-level data is a sketch. Your Growable Ground report scores blue lobelia against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Tennessee blue lobelia averages can't show:
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Growing guides for blue lobelia
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