false sunflower (Heliopsis helianthoides), photographi

Can I Grow False Sunflower in Tennessee?

USDA Zones 6a-8a · Plant zone range 4-9

Yes — Strong Match

false sunflower (zones 4-9) covers every zone Tennessee contains (6a-8a), so hardiness is not what limits it anywhere in the state.

False Sunflower in Tennessee — the short answer

False Sunflower in Tennessee: hardy in zones 4–9, full sun, against a state median of ~230 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
Tennessee zones
6a-8a
USDA PHZM 2023
Frost window
Mar 21 - Mar 29 – Nov 5 - Nov 12
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
193 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.

Score your parcel · free

Your yard isn't the whole zone.

Tennessee spans zones 6a-8a, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score false sunflower against your land's actual soil, sun, and frost.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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Tennessee is not one climate

A single Tennessee answer averages 95 counties whose growing seasons are 73 days apart — from 193 frost-free days in Johnson County to 266 in Shelby County. Which end of that your land sits nearer changes what false sunflower can finish before the first hard freeze.

193 daysJohnson County266 daysShelby County

The middle half of 95 counties runs 221235 days, with a median of 230 days — a 73-day span end to end.

Measured across 95 Tennessee counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. 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 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 false sunflower (USDA PHZM 2023):

Zone Comparison

False Sunflower Needs

  • USDA Zones: 4-9
  • Frost-Free Days: 90+
  • Sun: Full Sun
  • Mature size: 5 ft tall
  • Picking window: ~45 days of harvest
  • Drought tolerance: Medium

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)

4a
9b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 5.07.5

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 False Sunflower 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.

When to start the seed

Those dates are when false sunflower goes out, not when it starts. It is sown under cover about 8 weeks ahead, so counting back from Tennessee's late-side last freeze of Mar 29 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.

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.

Growing Season Fit

The zone check says false sunflower survives winter here. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

False Sunflower wants 90+ frost-free days; a typical Tennessee site sees ~230 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

False Sunflower likes near-neutral soil (pH 5-7.5). That's the common-ground band across Tennessee's silt loam and clay loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5.5 and 6.5 — worth knowing before you decide whether a Tennessee soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Tennessee site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Tennessee soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

What Else to Consider for False Sunflower 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 false sunflower — is covered on the Tennessee growing guide.

Timing shifts within Tennessee

False Sunflower needs about 90 days of frost-free season to complete its cycle. Even Johnson County — Tennessee’s shortest season at 193 frost-free days — clears that by 103 days, so season length isn’t the constraint anywhere in Tennessee. What varies is your own parcel.

Across Tennessee’s 95 counties the frost-free season runs from 193 days in Johnson County to 266 days in Shelby County — a spread of 73 days, which is why a single statewide planting date misleads. The median Tennessee county sees 230 frost-free days, leaving false sunflower about 140 days of slack on a typical parcel — room for a second sowing where the season runs long.

County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). False Sunflower's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Pollinator + Wildlife Value

False Sunflower draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, false sunflower 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 false sunflower, the canonical source is UT Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is False Sunflower native to Tennessee?

Yes — the USDA PLANTS Database (accessed 2026-07-01) documents False Sunflower 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 False Sunflower in Tennessee

When can I plant False Sunflower 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). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.

What hardiness zone is False Sunflower grown in across Tennessee?

Tennessee spans USDA hardiness zones 6a-8a (USDA ARS PHZM 2023). False Sunflower 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). False Sunflower needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.

Is False Sunflower native to Tennessee?

Yes — the USDA PLANTS Database (accessed 2026-07-01) documents False Sunflower as native to Tennessee. Planting it supports the pollinators and wildlife that evolved alongside it.

How should I amend the soil for False Sunflower in Tennessee?

False Sunflower prefers pH 5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Tennessee soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.

Will False Sunflower actually grow on my specific land in Tennessee?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores false sunflower against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in Tennessee

State-level data is a sketch. Your Growable Ground report scores false sunflower against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that Tennessee false sunflower averages can't show:

Your soil pHYour frost-free days — Tennessee averages 230Your sun & shade

We read public map data around Tennessee — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the Tennessee false sunflower average

Explore More

Explore Tennessee county by county

Tennessee carries 95 counties with their own USDA zone — a sample of the growing pages for false sunflower there:

Where else false sunflower grows

False Sunflower's zone band crosses state lines — these are the states closest to Tennessee 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 Tennessee

Tennessee has a growing page for 1,020 plants — a rotating sample of the rest of the shelf.

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