Generally — Most Areas
blue lobelia (zones 4-9) suits most of North Dakota (3b-4b) — zone 4 are in range, and the rest of the state is the exception.
Blue Lobelia in North Dakota — the short answer
Blue Lobelia in North Dakota: hardy in zones 4–9, against a state median of ~157 frost-free days.
- Plant zones
- 4-9
- 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
- North Dakota zones
- 3b-4b
- USDA PHZM 2023
- Frost window
- Apr 30 - May 6 – Oct 4 - Oct 9
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 141 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.
North Dakota spans zones 3b-4b, 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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North Dakota is not one climate
North Dakota’s winter-low ladder runs across 53 counties, from zone 3.5 in Bottineau County to zone 4.5 in Stutsman County. That is 10°F between the two counties’ average coldest night — the difference between blue lobelia overwintering in the ground and coming under cover.
The middle half of 53 counties runs 4–4 zones, with a median of 4 zones — a 1-zone span end to end.
Measured across 53 North Dakota 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 North Dakota Fits Best
Blue Lobelia is rated for zones 4–9 — a cold floor USDA puts at -30 to -20°F. Against North Dakota’s 53 counties that band holds in 47 of them, and the line runs at Barnes County (zone 4a), the coldest county still inside it.
Inside zones 4–9
47 counties
- Benson County · zone 4a
- Billings County · zone 4a
- Burke County · zone 4a
3 of 47 shown
Below the zone 4 floor
6 counties
- Bottineau County · zone 3b
- Cavalier County · zone 3b
- Divide County · zone 3b
3 of 6 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.
Even within North Dakota's zones 3b-4b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for blue lobelia (USDA PHZM 2023):
Zone Comparison
Blue Lobelia Needs
- USDA Zones: 4-9
- Mature size: 3 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Low
North Dakota Has
- USDA Zones: 3b-4b
- Last Hard Freeze (28°F): Apr 30 - May 6
- First Hard Freeze (28°F): Oct 4 - Oct 9
- Annual Rainfall: 14-22 inches
- Common Soils: Prairie loam, Clay (Red River Valley), Sandy loam
Plant Zone Range (zones 4-9)
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 Lobelia in North Dakota
The frost window
Across North Dakota, the last spring hard freeze (28°F) clears between Apr 30 and May 6, and the first fall hard freeze lands between Oct 4 and Oct 9 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 151-day window you can count on — up to 162 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
North Dakota runs as cold as USDA zone 3, 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 North Dakota; 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 Lobelia in North Dakota
Zone compatibility tells you about winter cold survival — but North Dakota growers also need to think about:
Extreme cold (-40F) and short growing season
Persistent wind desiccates plants
Low rainfall in western ND
What to actually do about these — and the constraints that apply to every North Dakota grower, not just blue lobelia — is covered on the North Dakota growing guide.
Where in North Dakota Blue Lobelia Is Zone-Hardy
Blue Lobelia is rated for USDA zones 4–9. 47 of North Dakota’s 53 counties fall inside that band. The coldest that does is Barnes County at zone 4a. 6 counties sit below the plant’s zone 4 floor, where an unprotected plant is relying on snow cover and a mild year. Where you are in North Dakota decides this one.
Across those 53 counties North Dakota’s winter-low ladder runs from zone 3b in Bottineau County to zone 4b in Stutsman 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. Bottineau County holds its last hard freeze (28°F) until about May 9, while Richland County is clear by Apr 23 — 16 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.
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 North Dakota's frost window — roughly 157 days, opening after the last 28°F freeze (Apr 30 - May 6) and closing at the first (Oct 4 - Oct 9), per NOAA Regional Climate Centers ACIS, 1991-2020.
North Dakota Cooperative Extension
For North Dakota-specific cultivar recommendations, planting calendars, and pest pressure for blue lobelia, the canonical source is NDSU Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Blue Lobelia native to North Dakota?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Blue Lobelia as native to North Dakota. 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 North Dakota
When can I plant Blue Lobelia in North Dakota?
North Dakota's last spring hard freeze (28°F) clears between Apr 30 and May 6, and the first fall hard freeze lands between Oct 4 and Oct 9 (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 North Dakota 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 North Dakota?
North Dakota spans USDA hardiness zones 3b-4b (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 North Dakota site have?
A typical North Dakota site sees ~157 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 North Dakota?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Blue Lobelia as native to North Dakota. Planting it supports the pollinators and wildlife that evolved alongside it.
Will Blue Lobelia actually grow on my specific land in North Dakota?
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 North Dakota
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 North Dakota blue lobelia averages can't show:
We read public map data around North Dakota — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the North Dakota blue lobelia average
Explore More
Growing guides for blue lobelia
Explore North Dakota county by county
North Dakota carries 53 counties with their own USDA zone — a sample of the growing pages for blue lobelia there:
Where else blue lobelia grows
Blue Lobelia's zone band crosses state lines — these are the states closest to North Dakota 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 North Dakota
North Dakota has a growing page for 745 plants — a rotating sample of the rest of the shelf.
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