Sunflower is an annual grown for its yellow blooms, which open in summer. It's hardy across USDA zones 2 through 11. Its summer flowers are a real draw for honeybees, native bees, and butterflies.
Sunflower — the short answer
Sunflower: grown in zones 2–11, full sun, pH 5.5–8, about 80 days to maturity.
- USDA zones
- 2–11
- 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
- Soil pH
- 5.5–8
- FAO ECOCROP
- Sun
- Full Sun
- Growable Ground Plant Database
- Days to Maturity
- 80 days
- USDA-NRCS; Johnny's
- Frost-kill temperature
- 32°F
- FAO ECOCROP
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 Sunflower on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether sunflower actually takes — and those shift from one yard to the next. Enter your address and we'll score sunflower against your land's real conditions.
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What Sunflower is
Sunflower grows as an annual and reaches around eight feet at maturity. It blooms yellow in summer.
How to grow Sunflower
Sunflower grows in USDA zones 2 through 11. Sunflower does best in full sun — at least 6 hours of direct sun a day — and soil from pH 5.5 to 8, on well-drained ground. It needs around 1,500 growing degree days to mature and a growing season of at least 70 frost-free days, which is why climate matters as much as soil.
USDA Zones
2-11
USDA PHZM 2023
Soil pH
5.5 - 8
FAO ECOCROP
Sun
Full Sun
Growable Ground plant catalog
Drainage
well (dry spells)
Growable Ground plant catalog
Frost Kill Temperature
32°F
Where cold starts killing growing tissue. Not a winter-survival floor — a dormant perennial takes far colder, which its hardiness zone answers.
FAO ECOCROP
Minimum Growing Temperature
41°F
Below this it stops growing rather than dies — a pace limit, not a survival limit.
FAO ECOCROP
Days to Maturity
80 days
Common sunflower; annual; seed harvest after head matures.
USDA-NRCS; Johnny's
GDD Required
1500+
Growing degree-days of accumulated warmth it needs to mature — humid summers reach this faster than cool coastal ones.
Growable Ground plant catalog
Mature Height
8 ft
Growable Ground plant catalog
Frost-Free Days
70+
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 sunflower in full sun with at least 6 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Sunflower prefers pH 5.5 to 8 (FAO ECOCROP). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at its peak
Cut sunflower blooms in the cool of the morning, just as they open, for the longest display.
Where Sunflower thrives
On hardiness alone, sunflower grows across most of the country — its range (USDA zones 2 through 11) is unusually wide. 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 2–11 spans average winter lows from -50°F to 50°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 48 outright and splits 3 more down the middle — and which side of that line your land sits on changes the answer.
Zones 2–11·Where Sunflower growsOpen map →
Continental US shown — Alaska and US Pacific territories sit outside the federal map's polygon dataset.
Where Sunflower stands, state by state
Sunflower is rated for zones 2–11 — a cold floor USDA puts at -50 to -40°F. Across the 50 states and DC, 48 sit fully inside that band, the line runs through 3 more, and 0 sit outside it — and inside every split state, the same line runs on at county grain.
Fully inside zones 2–11
48 states
3 of 48 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 Sunflower
Growing guides for sunflower
In rotation planning, sunflower 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 annual flower
Good to know
Good news for pet owners — sunflower isn't known to be toxic to dogs or cats. (Source: ASPCA.)
Sunflower is a standout pollinator plant — high value to bees and other pollinators. (Source: Xerces Society.)
Your land is one point inside Sunflower'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 Sunflower will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether sunflower 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 Sunflower
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 Sunflower in my zone?
Sunflower grows in USDA hardiness zones 2 through 11 (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 Sunflower?
Most growers plant sunflower after the last spring frost, once the soil has warmed, leaving enough of the season for its 70-day frost-free need. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Sunflower need?
Sunflower needs full sun — a spot that catches at least 6 hours of direct summer sun a day. In more shade it still grows, but usually gives a smaller, later crop. The catch is that a yard rarely gets even light everywhere — a fence, the house, or one tall tree can quietly take those hours. A Growable Ground report reads the real sun-hours across your land, canopy and buildings included, so you can pick the brightest bed before you plant.
What soil does Sunflower need?
Sunflower prefers soil pH 5.5 to 8, on well-drained ground (FAO ECOCROP). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Sunflower attract pollinators?
Yes — sunflower's flowers are a strong nectar and pollen source for honeybees, native bees, and butterflies. (Source: Xerces Society.)
Is Sunflower safe for pets?
Sunflower is not known to be toxic to dogs or cats based on available data. Always supervise pets around new plantings. (Source: ASPCA.)