Blue Lobelia is a perennial grown for its blooms, which open in summer and return year after year. It's hardy across USDA zones 4 through 9 and shrugs off deer. Its summer flowers are a real draw for native bees, butterflies, and hummingbirds.
Blue Lobelia — the short answer
Blue Lobelia: grown in zones 4–9.
- USDA 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
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — each tile names its own row's source, because per-field provenance varies.
Score Blue Lobelia on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether blue lobelia actually takes — and those shift from one yard to the next. Enter your address and we'll score blue lobelia against your land's real conditions.
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What Blue Lobelia is
Blue Lobelia grows as a perennial and reaches around three feet at maturity. It blooms in summer. It's also deer-resistant.
How to grow Blue Lobelia
Blue Lobelia grows in USDA zones 4 through 9.
USDA Zones
4-9
USDA PHZM 2023
Soil pH
Data pending
Sun
Data pending
Growable Ground plant catalog
Drainage
Data pending
Growable Ground plant catalog
Mature Height
3 ft
Growable Ground plant catalog
Frost-Free Days
0+
The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.
Growable Ground plant catalog
Start the season right
Plant blue lobelia in full sun.
Match the soil
Pull a soil test from your local Extension lab to confirm pH and drainage match blue lobelia's needs before planting.
Water steadily
Keep the root zone evenly moist through establishment. Match watering to the plant's drainage preference and your local rainfall.
Harvest at its peak
Cut blue lobelia blooms in the cool of the morning, just as they open, for the longest display.
Where Blue Lobelia thrives
Blue Lobelia is hardy across USDA zones 4 through 9. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
A USDA zone is a 10°F band of average annual extreme winter minimum, so zones 4–9 spans average winter lows from -30°F to 30°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 33 outright and splits 18 more down the middle — and which side of that line your land sits on changes the answer.
Zones 4–9·Where Blue Lobelia growsOpen map →
Where Blue Lobelia stands, state by state
Blue Lobelia is rated for zones 4–9 — a cold floor USDA puts at -30 to -20°F. Across the 50 states and DC, 33 sit fully inside that band, the line runs through 18 more, and 0 sit outside it — and inside every split state, the same line runs on at county grain.
Fully inside zones 4–9
33 states
3 of 33 shown
State zone extents: USDA Plant Hardiness Zone Map (PHZM) 2023. A zone is a 10°F band of average annual extreme minimum temperature, so a state that splits the band contains the boundary — its own page draws the county line, and a parcel report resolves which side your land sits on.
What grows around Blue Lobelia
Growing guides for blue lobelia
In rotation planning, blue lobelia counts as a Other — beds recover best when other crops don’t follow each other in the same spot year over year. (Growable Ground derivation — crop-rotation group from botanical family)
Related plants in perennial flower
Good to know
One caution for pet owners — blue lobelia is toxic to dogs and cats (moderate severity). Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: ASPCA.)
Blue Lobelia is a standout pollinator plant — high value to bees and other pollinators. (Source: Lady Bird Johnson Wildflower Center.)
Your land is one point inside Blue Lobelia's range
This page resolves to the species. Your state page draws the county line, and a report reads the parcel — the soil pH, drainage, sun, and frost dates on your exact ground, which no species average can see.
See if Blue Lobelia will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether blue lobelia actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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How we know this about Blue Lobelia
The figures above are cited per row, not per site: the pH band names this plant’s own source column, the three temperature figures each carry their own, and days-to-maturity cites the publication that actually lists it. All of it comes from the Growable Ground Plant Database — a compilation over FAO ECOCROP, USDA PLANTS, and university Extension sources, published openly with per-field provenance.
Grounded inUSDA PLANTS Database•USDA PHZM•ASPCA
Frequently asked questions
Can I grow Blue Lobelia in my zone?
Blue Lobelia grows in USDA hardiness zones 4 through 9 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
When should you plant Blue Lobelia?
Time blue lobelia to your own season rather than the calendar. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
What soil does Blue Lobelia need?
Specific pH data for blue lobelia is pending. A soil test from your local Extension lab confirms what your site needs.
Does Blue Lobelia attract pollinators?
Yes — blue lobelia's flowers are a strong nectar and pollen source for native bees, butterflies, and hummingbirds. (Source: Lady Bird Johnson Wildflower Center.)
Is Blue Lobelia safe for pets?
Blue Lobelia is toxic to pets (dogs,cats) with moderate severity. Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: ASPCA.)