mountain laurel (Kalmia latifolia), photographi

Can I Grow Mountain Laurel in Ohio?

USDA Zones 5b-7a · Plant zone range 5-11

Yes — Strong Match

mountain laurel (zones 5-11) covers every zone Ohio contains (5b-7a), so hardiness is not what limits it anywhere in the state.

Mountain Laurel in Ohio — the short answer

Mountain Laurel in Ohio: hardy in zones 5–11, shade, against a state median of ~208 frost-free days.

Plant zones
5-11
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
Ohio zones
5b-7a
USDA PHZM 2023
Frost window
Apr 5 - Apr 13 – Oct 31 - Nov 6
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
182 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.

Ohio spans zones 5b-7a, 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 mountain laurel 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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Ohio is not one climate

Ohio’s winter-low ladder runs across 88 counties, from zone 6 in Allen County to zone 7 in Scioto County. That is 10°F between the two counties’ average coldest night — the difference between mountain laurel overwintering in the ground and coming under cover.

6 zonesAllen County7 zonesScioto County

The middle half of 88 counties runs 66.5 zones, with a median of 6.5 zones — a 1-zone span end to end.

Measured across 88 Ohio 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 Ohio Fits Best

Even within Ohio's zones 5b-7a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for mountain laurel (USDA PHZM 2023):

Zone Comparison

Mountain Laurel Needs

  • USDA Zones: 5-11
  • Frost-Free Days: 150+
  • Sun: Shade
  • Mature size: 10 ft tall
  • Drought tolerance: High

Ohio Has

  • USDA Zones: 5b-7a
  • Last Hard Freeze (28°F): Apr 5 - Apr 13
  • First Hard Freeze (28°F): Oct 31 - Nov 6
  • Annual Rainfall: 34-42 inches
  • Common Soils: Glacial till, Clay loam, Silt loam

Plant Zone Range (zones 5-11)

5a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 4.55.5

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 Mountain Laurel in Ohio

The frost window

Across Ohio, the last spring hard freeze (28°F) clears between Apr 5 and Apr 13, and the first fall hard freeze lands between Oct 31 and Nov 6 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 201-day window you can count on — up to 215 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

Ohio runs as cold as USDA zone 5, and no sourced winter-hardiness floor is on record for mountain laurel, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether mountain laurel is a permanent planting or a replant-every-spring crop for you turns on your own zone within Ohio; check its hardiness range against that before treating it as long-lived ground.

Timing tuned to sub-state frost dates — Geauga 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 mountain laurel survives winter here. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

Mountain Laurel wants 150+ frost-free days; a typical Ohio site sees ~208 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a workable window — start indoors to bank time.

Chill hours

Mountain Laurel requires ~600 chill hours (32-45°F dormancy window). Ohio typically banks ~2500 chill hours per winter (from PRISM 1991-2020 climate normals), which keeps this plant on track.

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

Mountain Laurel prefers acidic soil (pH 4.5-5.5). Ohio's glacial till can run on the acidic side, which often aligns well — confirm with a soil test before planting.

Your land, not the state average

Ohio soil pH runs about 5.8–6.4, and that sits above mountain laurel's tolerated 4.5–5.5, so the typical Ohio parcel needs sulfur to bring it down. SSURGO maps it swinging by full points parcel to parcel, so your map unit, not the state number, decides whether mountain laurel needs lime or sulfur.

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. Ohio soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

What Else to Consider for Mountain Laurel in Ohio

Zone compatibility tells you about winter cold survival — but Ohio growers also need to think about:

Heavy clay soils across much of northern Ohio require amendment for drainage

Variable spring weather with late frost risk through mid-May

Japanese beetles and tomato hornworms are common garden pests

Wet springs can delay planting and promote root rot

Growing mountain laurel here specifically

Mountain Laurel does best acidic (pH 4.5–5.5); Ohio soils average near pH 6.1, alkaline enough to yellow its leaves as micronutrients lock away.

Work in elemental sulfur or acidic organic matter to pull your parcel toward pH 4.5–5.5, then retest. How to handle it →

What to actually do about these — and the constraints that apply to every Ohio grower, not just mountain laurel — is covered on the Ohio growing guide.

Timing shifts within Ohio

Ohio isn't one climate. In Geauga County, the last hard freeze (28°F) holds until about Apr 22 — roughly 13 days later than the recorded state median — so plant mountain laurel to your county's window, not the statewide date.

Mountain Laurel needs about 150 days of frost-free season to complete its cycle. Even Columbiana County — Ohio’s shortest season at 182 frost-free days — clears that by 32 days, so season length isn’t the constraint anywhere in Ohio. What varies is your own parcel.

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"). Mountain Laurel's 150-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

Mountain Laurel draws native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, mountain laurel can only work that bloom inside Ohio's frost window — roughly 208 days, opening after the last 28°F freeze (Apr 5 - Apr 13) and closing at the first (Oct 31 - Nov 6), per NOAA Regional Climate Centers ACIS, 1991-2020.

Good to Know Before You Plant Mountain Laurel

Mountain Laurel is listed as toxic to dogs, cats, horses (all) at a severe level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.

Ohio Cooperative Extension

For Ohio-specific cultivar recommendations, planting calendars, and pest pressure for mountain laurel, the canonical source is Ohio State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Mountain Laurel native to Ohio?

Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Mountain Laurel as native to Ohio. 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 Mountain Laurel in Ohio

When can I plant Mountain Laurel in Ohio?

Ohio's last spring hard freeze (28°F) clears between Apr 5 and Apr 13, and the first fall hard freeze lands between Oct 31 and Nov 6 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Mountain Laurel, so this page does not state whether it overwinters in Ohio 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 Mountain Laurel grown in across Ohio?

Ohio spans USDA hardiness zones 5b-7a (USDA ARS PHZM 2023). Mountain Laurel carries a range of zones 5-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical Ohio site have?

A typical Ohio site sees ~208 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Mountain Laurel needs 150+ 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 Geauga, the freeze-free season runs shorter than the state average, so verify your own county's window.

Is Mountain Laurel native to Ohio?

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

How should I amend the soil for Mountain Laurel in Ohio?

Mountain Laurel prefers pH 4.5-5.5 (USDA PLANTS). Most Ohio soils run mildly acidic to neutral; many sites land near this band naturally, and a soil test plus targeted sulfur or organic amendment closes any gap.

Will Mountain Laurel actually grow on my specific land in Ohio?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores mountain laurel 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 Ohio

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

Three things about your lot that Ohio mountain laurel averages can't show:

Your soil pHYour frost-free days — Ohio averages 208Your sun & shade

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

25+ data sources read at your address, not the Ohio mountain laurel average

Explore More

Explore Ohio county by county

Ohio carries 88 counties with their own USDA zone — a sample of the growing pages for mountain laurel there:

Where else mountain laurel grows

Mountain Laurel's zone band crosses state lines — these are the states closest to Ohio 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 Ohio

Ohio 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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