Unlikely — Zone Mismatch
calopo (zones 10-12) does not overlap with New Jersey's zone range (6a-8a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Calopo is hardy to zone 10, and the warmest ground in New Jersey is zone 8 — 2 zones short. Planted in open ground it will not survive a New Jersey winter. To grow it here, grow calopo under glass — a greenhouse is the only lift this wide the engine models.
A greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 10-12 (plant) against 6-8 (New Jersey). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
Your yard isn't the whole zone.
Calopo is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical New Jersey site runs ~222 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score calopo against your land's actual frost dates, sun, and soil.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Zone Comparison
Calopo Needs
- USDA Zones: 10-12
- Frost-Free Days: 120+
- Sun: Full Sun
- Mature size: 1 ft tall
- Drought tolerance: Low
New Jersey Has
- USDA Zones: 6a-8a
- Last Hard Freeze (28°F): Mar 26 - Apr 4
- First Hard Freeze (28°F): Nov 5 - Nov 17
- Annual Rainfall: 40-50 inches
- Common Soils: Sandy loam (Pine Barrens), Silt loam, Clay
Plant Zone Range (zones 10-12)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Calopo in New Jersey
The frost window
Across New Jersey, the last spring hard freeze (28°F) clears between Mar 26 and Apr 4, and the first fall hard freeze lands between Nov 5 and Nov 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 215-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.
Frost tenderness
Calopo is frost-tender — its listed minimum temperature is 64.4°F (USDA PLANTS Database) — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does.
Timing tuned to sub-state frost dates — Morris County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. 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 calopo does not survive a New Jersey winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on New Jersey under protection.
Frost-free days
Calopo wants 120+ frost-free days; a typical New Jersey site sees ~222 (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
Calopo tolerates a wide pH range (pH 4.3-8) — 3.7 units, acid ground through alkaline — so soil acidity is rarely what limits it in New Jersey. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 4.5 and 5.7 — worth knowing before you decide whether a New Jersey soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your New Jersey site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 14.3% of New Jersey as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Calopo has low drought tolerance, so it is the fast-draining end that will cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. New Jersey soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Calopo in New Jersey — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 10-12 (USDA PLANTS Database)
- State Zones: 6a-8a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Mar 26 - Apr 4 to Nov 5 - Nov 17 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Calopo in New Jersey
Zone compatibility tells you about winter cold survival — but New Jersey growers also need to think about:
Sandy Pine Barrens soils are nutrient-poor
Urban heat island effects in northern NJ
Deer browse is extreme in suburban areas
Growing calopo here specifically
Calopo likes pH 4.3–8.0 and takes cold to about 64°F, yet neither saves it from wet feet — SSURGO maps about 14.3% of New Jersey poorly-drained, where its roots sit and rot.
Set calopo high on bermed, grit-amended ground so winter and storm water drain away from the roots. How to handle it →
What to actually do about these — and the constraints that apply to every New Jersey grower, not just calopo — is covered on the New Jersey growing guide.
Timing shifts within New Jersey
New Jersey isn't one climate. In Morris County, the last hard freeze (28°F) holds until about Apr 11 — roughly 11 days later than the recorded state median — so plant calopo to your county's window, not the statewide date.
Calopo needs about 120 days of frost-free season to complete its cycle. Even Sussex County — New Jersey’s shortest season at 196 frost-free days — clears that by 76 days, so season length isn’t the constraint anywhere in New Jersey. 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"). Calopo's 120-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
Calopo draws honeybees (low value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, calopo can only work that bloom inside New Jersey's frost window — roughly 222 days, opening after the last 28°F freeze (Mar 26 - Apr 4) and closing at the first (Nov 5 - Nov 17), per NOAA Regional Climate Centers ACIS, 1991-2020.
New Jersey Cooperative Extension
For New Jersey-specific cultivar recommendations, planting calendars, and pest pressure for calopo, the canonical source is Rutgers Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Calopo native to New Jersey?
No — the USDA PLANTS Database lists Calopo as introduced rather than native in the Lower 48, so it is not part of New Jersey's native flora. It grows here as a garden plant; pairing it with a few New Jersey natives keeps local pollinators fed too.
Looking for plants that belong here? The New Jersey 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 Calopo in New Jersey
When can I plant Calopo in New Jersey?
New Jersey's last spring hard freeze (28°F) clears between Mar 26 and Apr 4, and the first fall hard freeze lands between Nov 5 and Nov 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Calopo is frost-tender — its listed minimum temperature is 64.4°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
What hardiness zone is Calopo grown in across New Jersey?
New Jersey spans USDA hardiness zones 6a-8a (USDA ARS PHZM 2023). Calopo carries a range of zones 10-12, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical New Jersey site have?
A typical New Jersey site sees ~222 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Calopo needs 120+ 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 Morris, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Calopo native to New Jersey?
No — the USDA PLANTS Database lists Calopo as introduced rather than native in the Lower 48, so it is not part of New Jersey's native flora. It grows here as a garden plant; pairing it with a few New Jersey natives keeps local pollinators fed too.
How should I amend the soil for Calopo in New Jersey?
Calopo tolerates pH 4.3-8 and well (dry spells) drainage (FAO ECOCROP). That is a 3.7-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a New Jersey site — amend for drainage and organic matter first.
Will Calopo actually grow on my specific land in New Jersey?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores calopo 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 New Jersey
State-level data is a sketch. Your Growable Ground report scores calopo against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that New Jersey calopo averages can't show:
We read public map data around New Jersey — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New Jersey calopo average
Explore More
Growing guides for calopo
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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