Conditional — Some Areas
lemon verbena (zones 8-11) reaches only part of Idaho (3b-8a): zone 8 are in range, so where you are in the state decides it.
One zone short — what would close it
Lemon Verbena is hardy to zone 8, and the warmest ground in Idaho is zone 7 — 1 zone short. Planted in open ground it will not survive a Idaho winter. To grow it here, grow lemon verbena in a hoop house or unheated greenhouse — its modeled 1.5-zone lift covers this gap.
A hoop house or unheated greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 8-11 (plant) against 4-7 (Idaho). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['hoop_house'] (+1.5 zones) via api/fast_sections.py Unlock Engine v2.
Lemon Verbena in Idaho — the short answer
Lemon Verbena in Idaho: hardy in zones 8–11, full sun, against a state median of ~160 frost-free days.
- Plant zones
- 8-11
- 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
- Idaho zones
- 3b-8a
- USDA PHZM 2023
- Frost window
- Apr 26 - May 17 – Oct 1 - Oct 17
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 94 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 120 days
- Growable Ground Plant Database
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.
Idaho spans zones 3b-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 lemon verbena against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Idaho is not one climate
Idaho’s winter-low ladder runs across 44 counties, from zone 5 in Bear Lake County to zone 7 in Payette County. That is 20°F between the two counties’ average coldest night — the difference between lemon verbena overwintering in the ground and coming under cover.
The middle half of 44 counties runs 5.5–6.5 zones, with a median of 6 zones — a 2-zone span end to end.
Measured across 44 Idaho 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 Lemon Verbena Stands in Idaho
Lemon Verbena is rated for zones 8–11 — a cold floor USDA puts at 10 to 20°F. No Idaho county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Idaho winters, not about lemon verbena.
Below the zone 8 floor
44 counties
- Bear Lake County · zone 5a
- Caribou County · zone 5a
- Fremont County · zone 5a
3 of 44 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.
Zone Comparison
Lemon Verbena Needs
- USDA Zones: 8-11
- Frost-Free Days: 365+
- Sun: Full Sun
- Mature size: 6 ft tall
- Picking window: ~120 days of harvest
- Drought tolerance: Medium
Idaho Has
- USDA Zones: 3b-8a
- Last Hard Freeze (28°F): Apr 26 - May 17
- First Hard Freeze (28°F): Oct 1 - Oct 17
- Annual Rainfall: 8-35 inches
- Common Soils: Volcanic ash, Silt loam, Sandy loam
Plant Zone Range (zones 8-11)
Preferred Soil pH
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 Lemon Verbena in Idaho
The frost window
Across Idaho, the last spring hard freeze (28°F) clears between Apr 26 and May 17, and the first fall hard freeze lands between Oct 1 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 137-day window you can count on — up to 174 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 lemon verbena goes out, not when it starts. It is sown under cover about 10 weeks ahead, so counting back from Idaho's late-side last freeze of May 17 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Winter standing
Idaho runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for lemon verbena, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether lemon verbena is a permanent planting or a replant-every-spring crop for you turns on your own zone within Idaho; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Valley County, not the statewide average.
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 lemon verbena survives winter in part of Idaho, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Lemon Verbena wants 365+ frost-free days; a typical Idaho site sees ~160 (NOAA Regional Climate Centers ACIS, 1991-2020) — 205 days short of what it needs. A typical Idaho season does not carry this crop to harvest outdoors, and a gap that size is not one an earlier sowing date or a faster cultivar closes; growing it here means growing it under cover.
Growing degree days
Lemon Verbena needs ~2000 GDD (base 50°F) to ripen. The state median runs ~1187 GDD (from PRISM 1991-2020 climate normals), so Idaho's typical season runs short on heat — pick a south-facing site and consider season extension.
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
Lemon Verbena likes near-neutral soil (pH 5-7.5). That's the common-ground band across Idaho's volcanic ash and silt 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 7 — worth knowing before you decide whether a Idaho soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Idaho site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Idaho's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Lemon Verbena needs about 19 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how lemon verbena performs.
Check your parcel → Source: USDA NRCS SSURGO.
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. Idaho soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant lemon verbena for food
Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before lemon verbena goes in. What follows is Idaho’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.
Safe to Grow Here?
What the federal record shows across Idaho — and how to grow with it.
We checked the federal record across Idaho — 21,100 documented sites across 8 of the 9 source types we track.
The most significant on record: 215 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Idaho carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources Checked
across Idaho
Severity Distribution
across Idaho
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Idaho, two things run higher than the national average across Idaho — Mining (3,980 sites) and Nitrate (9,840 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What Else to Consider for Lemon Verbena in Idaho
Zone compatibility tells you about winter cold survival — but Idaho growers also need to think about:
Short growing season at higher elevations
Arid conditions require irrigation in most of the state
Cold winter snaps can reach -30F in mountain valleys
Growing lemon verbena here specifically
Lemon Verbena needs pH 5.0–7.5; Idaho's dominant silt loam soils may or may not deliver that, so your parcel's SSURGO map unit is the real test.
Start with a soil test on your own ground and adjust pH and texture to fit lemon verbena's 5.0–7.5 range. How to handle it →
What to actually do about these — and the constraints that apply to every Idaho grower, not just lemon verbena — is covered on the Idaho growing guide.
Timing shifts within Idaho
Idaho isn't one climate. In Valley County, the last hard freeze (28°F) holds until about Jun 14 — roughly 42 days later than the recorded state median — so plant lemon verbena to your county's window, not the statewide date.
Lemon Verbena needs about 365 days of frost-free season to complete its cycle. No Idaho county gives it that outdoors: even Nez Perce County, the state’s longest season at 216 frost-free days, falls 149 days short — so it needs transplants, a short-season variety, or covered growing.
Across Idaho’s 44 counties the frost-free season runs from 94 days in Valley County to 216 days in Nez Perce County — a spread of 122 days, which is why a single statewide planting date misleads. The median Idaho county sees 160 frost-free days, which is 205 days short of what lemon verbena needs — so on a typical Idaho parcel this is a transplant-or-protect crop, not a direct-sow one.
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"). Lemon Verbena's 365-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
Lemon Verbena draws honeybees, native bees, and butterflies (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, lemon verbena can only work that bloom inside Idaho's frost window — roughly 160 days, opening after the last 28°F freeze (Apr 26 - May 17) and closing at the first (Oct 1 - Oct 17), per NOAA Regional Climate Centers ACIS, 1991-2020.
Recommended Lemon Verbena Varieties for Idaho
Idaho publishes no state variety trial for lemon verbena, so we won't invent a "best for Idaho" list. Choose types rated to your USDA hardiness zone (3b-8a), and confirm winter survival and drainage against your own parcel.
Idaho Cooperative Extension
For Idaho-specific cultivar recommendations, planting calendars, and pest pressure for lemon verbena, the canonical source is University of Idaho Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Lemon Verbena native to Idaho?
No — the USDA PLANTS Database lists Lemon Verbena as introduced rather than native in the Lower 48, so it is not part of Idaho's native flora. It grows here as a garden plant; pairing it with a few Idaho natives keeps local pollinators fed too.
Looking for plants that belong here? The Idaho growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Lemon Verbena in Idaho
When can I plant Lemon Verbena in Idaho?
Idaho's last spring hard freeze (28°F) clears between Apr 26 and May 17, and the first fall hard freeze lands between Oct 1 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Lemon Verbena, so this page does not state whether it overwinters in Idaho 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 Lemon Verbena grown in across Idaho?
Idaho spans USDA hardiness zones 3b-8a (USDA ARS PHZM 2023). Lemon Verbena carries a range of zones 8-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Idaho site have?
A typical Idaho site sees ~160 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Lemon Verbena needs 365+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Valley, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Lemon Verbena native to Idaho?
No — the USDA PLANTS Database lists Lemon Verbena as introduced rather than native in the Lower 48, so it is not part of Idaho's native flora. It grows here as a garden plant; pairing it with a few Idaho natives keeps local pollinators fed too.
How should I amend the soil for Lemon Verbena in Idaho?
Lemon Verbena prefers pH 5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Idaho soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Lemon Verbena actually grow on my specific land in Idaho?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores lemon verbena 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 Idaho
State-level data is a sketch. Your Growable Ground report scores lemon verbena against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Idaho lemon verbena averages can't show:
We read public map data around Idaho — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Idaho lemon verbena average
Explore More
Growing guides for lemon verbena
Explore Idaho county by county
Idaho carries 44 counties with their own USDA zone — a sample of the growing pages for lemon verbena there:
Where else lemon verbena grows
Lemon Verbena's zone band crosses state lines — these are the states closest to Idaho 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 Idaho
Idaho has a growing page for 893 plants — a rotating sample of the rest of the shelf.
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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