Unlikely — Zone Mismatch
caladium (zones 9-11) does not overlap with Rhode Island's zone range (6b-7b). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Caladium is hardy to zone 9, and the warmest ground in Rhode Island is zone 7 — 2 zones short. Planted in open ground it will not survive a Rhode Island winter. To grow it here, grow caladium in an earth-sheltered greenhouse — its modeled 2.5-zone lift covers this gap.
An earth-sheltered greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 9-11 (plant) against 6-7 (Rhode Island). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['earth_sheltered'] (+2.5 zones) via api/fast_sections.py Unlock Engine v2.
Caladium in Rhode Island — the short answer
Caladium in Rhode Island: hardy in zones 9–11, full sun, against a state median of ~225 frost-free days.
- Plant zones
- 9-11
- 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
- Rhode Island zones
- 6b-7b
- USDA PHZM 2023
- Frost window
- Mar 27 - Apr 3 – Nov 7 - Nov 21
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 210 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.
Your yard isn't the whole zone.
Rhode Island spans zones 6b-7b, 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 caladium 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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Where Caladium Stands in Rhode Island
Caladium is rated for zones 9–11 — a cold floor USDA puts at 20 to 30°F. No Rhode Island 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 Rhode Island winters, not about caladium.
Below the zone 9 floor
5 counties
- Kent County · zone 6b
- Providence County · zone 6b
- Bristol County · zone 7a
3 of 5 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
Caladium Needs
- USDA Zones: 9-11
- Frost-Free Days: 180+
- Sun: Full Sun
- Mature size: 2 ft tall
- Picking window: ~90 days of harvest
- Drought tolerance: Low
Rhode Island Has
- USDA Zones: 6b-7b
- Last Hard Freeze (28°F): Mar 27 - Apr 3
- First Hard Freeze (28°F): Nov 7 - Nov 21
- Annual Rainfall: 44-52 inches
- Common Soils: Glacial till, Sandy loam, Coastal sand
Plant Zone Range (zones 9-11)
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 Caladium in Rhode Island
The frost window
Across Rhode Island, the last spring hard freeze (28°F) clears between Mar 27 and Apr 3, and the first fall hard freeze lands between Nov 7 and Nov 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 218-day window you can count on — up to 239 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 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 caladium does not survive a Rhode Island 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 Rhode Island under protection.
Frost-free days
Caladium wants 180+ frost-free days; a typical Rhode Island site sees ~225 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a workable window — start indoors to bank time.
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
Caladium tolerates a wide pH range (pH 4.3-8.2) — 3.9 units, acid ground through alkaline — so soil acidity is rarely what limits it in Rhode Island. 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 5.5 and 6.5 — worth knowing before you decide whether a Rhode Island soil test result is a problem or just a number. Drainage matters: this plant wants poorly (saturated >50% of year), well (dry spells). If your Rhode Island site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Rhode Island's soils run mostly fine sandy loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Caladium 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 caladium 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. Rhode Island soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Caladium in Rhode Island
Zone compatibility tells you about winter cold survival — but Rhode Island growers also need to think about:
Small lot sizes limit garden space in much of the state
Salt spray affects coastal plantings
Rocky glacial soils need clearing
Growing caladium here specifically
Rhode Island's soils run mostly fine sandy loam (Inceptisols), and whether that suits caladium's pH 4.3–8.2 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward caladium's 4.3–8.2 target before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Rhode Island grower, not just caladium — is covered on the Rhode Island growing guide.
Timing shifts within Rhode Island
Caladium needs about 180 days of frost-free season to complete its cycle. Even Providence County — Rhode Island’s shortest season at 210 frost-free days — clears that by 30 days, so season length isn’t the constraint anywhere in Rhode Island. 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"). Caladium's 180-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Good to Know Before You Plant Caladium
Caladium is listed as toxic to dogs, cats (all) at a moderate level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Rhode Island this is a one-season plant and the first hard freeze (Nov 7 - Nov 21) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Caladium Varieties for Rhode Island
Rhode Island publishes no state variety trial for caladium, so we won't invent a "best for Rhode Island" list. Choose types rated to your USDA hardiness zone (6b-7b), and confirm winter survival and drainage against your own parcel.
Rhode Island Cooperative Extension
For Rhode Island-specific cultivar recommendations, planting calendars, and pest pressure for caladium, the canonical source is URI Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Caladium in Rhode Island
When can I plant Caladium in Rhode Island?
Rhode Island's last spring hard freeze (28°F) clears between Mar 27 and Apr 3, and the first fall hard freeze lands between Nov 7 and Nov 21 (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 Caladium grown in across Rhode Island?
Rhode Island spans USDA hardiness zones 6b-7b (USDA ARS PHZM 2023). Caladium carries a range of zones 9-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Rhode Island site have?
A typical Rhode Island site sees ~225 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Caladium needs 180+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
How should I amend the soil for Caladium in Rhode Island?
Caladium tolerates pH 4.3-8.2 and poorly (saturated >50% of year), well (dry spells) drainage (FAO ECOCROP). That is a 3.9-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Rhode Island site — amend for drainage and organic matter first.
Will Caladium actually grow on my specific land in Rhode Island?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores caladium 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 Rhode Island
State-level data is a sketch. Your Growable Ground report scores caladium against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Rhode Island caladium averages can't show:
We read public map data around Rhode Island — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Rhode Island caladium average
Explore More
Growing guides for caladium
Explore Rhode Island county by county
Rhode Island carries 5 counties with their own USDA zone — a sample of the growing pages for caladium there:
Where else caladium grows
Caladium's zone band crosses state lines — these are the states closest to Rhode Island 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 Rhode Island
Rhode Island has a growing page for 889 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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