Canadian Cultivar Hardiness — Cold-Hardy Cultivars by Zone
Which named variety survives your winter? A free, sourced reference table of 51 ornamental and fruit cultivars across 9 plant groups, rated by Natural Resources Canada plant hardiness zone — cross-checked against our growing guides, borderline ratings flagged.
At a glance: This dataset rates 51 named cultivars across 9 plant groups by their hardy-to Natural Resources Canada zone. The hardiest, rated to Zone 2, are Rugosa (Rosa rugosa), Common lilac (Syringa vulgaris), Preston hybrids (S. x prestoniae) — several the product of Canadian cold-climate breeding (Agriculture Canada's Explorer & Parkland roses, Ottawa's Preston lilacs). Cultivar hardiness is breeder/nursery-rated, so treat a variety rated right at your zone as borderline and give it a sheltered spot. Free to cite with a link to this page.
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All 51 cultivars — plant, cultivar, type, hardy-to zone, notes and source — as a free CSV.
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Canadian cultivar cold-hardiness by zone, compiled by GrowersGuide.ca (NRCan hardiness zones; Canadian breeding-program sources noted per row)
Cultivars by Hardiness Zone
Scan by your zone: every cultivar rated to a given zone also grows in every milder (higher-numbered) zone. So a Zone 3 gardener can grow everything rated Zone 2 and 3.
| Hardy to zone | Cultivars | Examples |
|---|---|---|
| Z2 | 3 | Rugosa (Rosa rugosa), Common lilac (Syringa vulgaris), Preston hybrids (S. x prestoniae) |
| Z3 | 18 | 'Limelight' (paniculata), 'Little Lime' (paniculata), 'Quick Fire' (paniculata), 'Bobo' (paniculata)… |
| Z4 | 12 | 'Autumn Gold', 'Princeton Sentry', 'Magyar', 'Jade Butterfly'… |
| Z4b | 3 | 'Emperor I', 'Sango Kaku' (Coral Bark), 'Beni Kawa' |
| Z5 | 13 | 'Bloodgood', species, 'Gold Rush' / 'Ogon', 'Miss Grace'… |
| Z5b | 1 | 'Osakazuki' |
| Z6 | 1 | 'Susquehanna' |
The Full Table — Every Cultivar by Plant
Grouped by plant, hardiest cultivar first. "Hardy to" is the coldest Natural Resources Canada zone where the cultivar is a reasonable bet with the right site — treat the coldest figure as borderline.
Lilac (4 cultivars, hardiest Zone 2)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| Common lilac (Syringa vulgaris) | Shrub | Z2 | Among Canada's hardiest shrubs; needs winter chill (poor in Zone 7b+) |
| Preston hybrids (S. x prestoniae) | Shrub | Z2 | Bred in Ottawa by Isabella Preston; late-blooming |
| 'Miss Kim' (Korean, S. pubescens) | Shrub | Z3 | Compact, fragrant; good fall colour |
| Japanese tree lilac 'Ivory Silk' (S. reticulata) | Small tree | Z3 | Creamy-white June bloom; small street tree |
Rose (8 cultivars, hardiest Zone 2)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| Rugosa (Rosa rugosa) | Species shrub rose | Z2 | Hardiest garden rose; salt- and wind-tolerant |
| 'John Cabot' (Explorer) | Shrub/climber rose | Z3 | Canadian-bred Explorer climber |
| 'William Baffin' (Explorer) | Shrub/climber rose | Z3 | Vigorous Explorer climber; survives to Zone 2 under snow |
| 'Champlain' (Explorer) | Shrub rose | Z3 | Recurrent red Explorer shrub rose |
| 'Henry Kelsey' (Explorer) | Climber rose | Z3 | Red Explorer climber |
| 'Morden Blush' (Parkland) | Shrub rose | Z3 | Parkland/Morden series; very long bloom |
| 'Prairie Joy' (Parkland) | Shrub rose | Z3 | Hardy Canadian-bred shrub rose |
| 'Winnipeg Parks' (Parkland) | Shrub rose | Z3 | Parkland series; compact red |
Clematis (5 cultivars, hardiest Zone 3)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| 'Jackmanii' | Vine | Z3 | The Canadian workhorse; group 3, hard-prune each spring |
| alpina (Blue Dancer, Constance) | Vine | Z3 | Spring species; very hardy; group 1 |
| macropetala (Markham's Pink) | Vine | Z3 | Nodding spring flowers; very hardy |
| viticella 'Polish Spirit' | Vine | Z4 | Group 3; disease-resistant |
| 'Nelly Moser' / 'The President' | Vine | Z5 | Large-flowered types; more reliable Zone 5+ |
Hydrangea (8 cultivars, hardiest Zone 3)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| 'Limelight' (paniculata) | Shrub | Z3 | Panicle; chartreuse-to-pink; blooms on new wood (reliable bloom) |
| 'Little Lime' (paniculata) | Shrub | Z3 | Compact 'Limelight' |
| 'Quick Fire' (paniculata) | Shrub | Z3 | Earliest panicle bloomer (June) |
| 'Bobo' (paniculata) | Shrub | Z3 | Dwarf panicle |
| 'Annabelle' (arborescens) | Shrub | Z3 | Smooth hydrangea; blooms on new wood; stems can flop |
| 'Incrediball' (arborescens) | Shrub | Z3 | Strong-stemmed 'Annabelle' — no flopping |
| 'Vanilla Strawberry' (paniculata) | Shrub | Z4 | White-to-strawberry-red panicles |
| 'Endless Summer' (macrophylla) | Shrub | Z5 | Reblooming bigleaf mophead; borderline Zone 4 with a winter burlap wrap |
Ginkgo (6 cultivars, hardiest Zone 4)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| 'Autumn Gold' | Shade tree (male clone) | Z4 | Broad, symmetrical male; uniform gold fall colour; fruitless |
| 'Princeton Sentry' | Shade tree (male clone) | Z4 | Narrow columnar (fastigiate) male; fruitless; for tight spaces |
| 'Magyar' | Shade tree (male clone) | Z4 | Upright pyramidal male with a strong central leader |
| 'Jade Butterfly' | Dwarf tree (male clone) | Z4 | Compact, vase-shaped; distinctive butterfly-like leaves |
| 'Mariken' | Dwarf tree (male clone) | Z4 | Dwarf globe, often sold top-grafted as a standard |
| 'Troll' | Dwarf tree (male clone) | Z4 | Very compact dwarf bun; containers/collectors |
Japanese maple (6 cultivars, hardiest Zone 4)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| 'Mikawa Yatsubusa' | Dwarf | Z4 | Very compact dwarf; best container palmatum for Canada |
| 'Emperor I' | Small tree | Z4b | Upright red; hardier than 'Bloodgood' by ~1 zone |
| 'Sango Kaku' (Coral Bark) | Small tree | Z4b | Coral-red winter bark; needs shelter from winter wind |
| 'Beni Kawa' | Small tree | Z4b | Like 'Sango Kaku', slightly hardier |
| 'Bloodgood' | Small tree | Z5 | Standard upright red; struggles in Zone 4 without a sheltered site |
| 'Osakazuki' | Small tree | Z5b | Green leaves; the most vivid scarlet fall colour of any cultivar |
Magnolia (4 cultivars, hardiest Zone 4)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| Star magnolia (M. stellata) | Small tree | Z4 | Early white stars; hardier than saucer types |
| 'Merrill' (M. x loebneri) | Small tree | Z4 | Vigorous, white, fragrant |
| Little Girl series (Ann, Jane, Susan) | Large shrub | Z4 | Later bloom dodges late spring frost |
| Saucer magnolia (M. x soulangeana) | Small tree | Z5 | Showiest; April bloom often caught by late frost in Zone 5 |
Dawn redwood (4 cultivars, hardiest Zone 5)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| species | Deciduous conifer | Z5 | Fast, full-size; borderline Zone 4b in shelter; wants steady moisture |
| 'Gold Rush' / 'Ogon' | Deciduous conifer | Z5 | Golden foliage; slower and smaller; give a sheltered site |
| 'Miss Grace' | Deciduous conifer (dwarf) | Z5 | Weeping dwarf for a specimen spot |
| 'North Light' (Schirrmann's Nordlicht) | Deciduous conifer (dwarf) | Z5 | Slow, compact; cream-flushed new growth |
Pawpaw (6 cultivars, hardiest Zone 5)
| Cultivar | Type | Hardy to | Notes |
|---|---|---|---|
| 'NC-1' | Fruit tree | Z5 | Cold-hardy, early-ripening, Ontario roots; tree hardy to 4b (fruit may not finish in coldest gardens) |
| 'Sunflower' | Fruit tree | Z5 | Vigorous, large fruit; more self-fertile (still plant two) |
| 'Shenandoah' | Fruit tree | Z5 | Peterson selection; excellent flavour and texture |
| 'Mango' | Fruit tree | Z5 | Earlier ripening; useful insurance in cooler Zone 5 |
| 'Pennsylvania Golden' | Fruit tree | Z5 | Early ripening |
| 'Susquehanna' | Fruit tree | Z6 | Peterson selection; large fruit, few seeds; best Zone 6+ |
Methodology & Sources
- What "hardy to Zone X" means: the coldest Natural Resources Canada plant hardiness zone (planthardiness.gc.ca) where the cultivar is a reasonable bet with correct siting. Every milder (higher-numbered) zone can grow it too.
- Sources. Ratings are compiled from breeder, nursery and botanical-garden records and from named Canadian cold-climate breeding programs — Agriculture and Agri-Food Canada's Explorer and Parkland/Morden rose series, and Isabella Preston's Ottawa-bred lilacs — noted per row in the CSV.
- Cross-checked. Every rating is reconciled against this site's own growing guides, so the dataset never contradicts our published advice.
- Honest caveat. Cultivar hardiness is not measured data like the ECCC frost normals — it is breeder/nursery-rated and varies with microclimate, snow cover, wind and siting. Treat any cultivar rated right at your zone as borderline; a sheltered spot and good drainage often buy a half-zone.
- Live-computed. The by-zone counts, hardiest-cultivar figures and per-plant groupings on this page are computed from the downloadable CSV on every load — nothing is hand-typed.
For collectors, garden clubs, societies & nurseries
This table is free to quote and republish — in newsletters, society bulletins, plant-sale handouts or your own site — with credit to GrowersGuide.ca and a link to this page. Growing a cultivar we haven't rated, or have rated too conservatively for your area? Tell us — corrections and additions from experienced Canadian growers make this dataset better: zusashicanada@gmail.com.
We'd rather cite your Zone-3 success with a "borderline" cultivar than leave it off the list.
Use of This Data
The compiled dataset on this page is free to use with attribution to GrowersGuide.ca (a link to this page is sufficient). Where a rating derives from a named breeding program (Explorer/Parkland roses, Preston lilacs) or breeder, please credit that primary source too. Cultivar hardiness is a guide, not a guarantee — provided as-is, without warranty; verify against your local zone and conditions before buying.
Turn the Data Into a Planting Decision
Frequently Asked Questions
What is a cultivar hardiness rating, and how reliable is it?
A cultivar hardiness rating is the coldest Natural Resources Canada hardiness zone in which a specific named variety is a reasonable bet. Unlike Environment and Climate Change Canada's frost normals — which are measured climate data — cultivar hardiness is rated by breeders, nurseries, botanical gardens and Canadian breeding programs, so it is more variable and microclimate-sensitive. Treat a cultivar rated right at your zone as borderline and give it a sheltered spot. Every rating in this dataset is cross-checked against our own growing guides.
Which cultivars in this dataset are the hardiest?
The hardiest entries are rated to Natural Resources Canada Zone 2: Rugosa (Rosa rugosa), Common lilac (Syringa vulgaris), Preston hybrids (S. x prestoniae). These survive most of the Prairies and near-northern gardens. Canadian breeding programs are the reason several exist — Agriculture Canada's Explorer and Parkland/Morden rose series and Isabella Preston's Ottawa-bred lilacs were developed specifically for cold Canadian winters.
Why not just use a US cultivar hardiness list?
Because US "cold-hardy cultivar" lists are usually written for USDA Zone 5–7 — mild by Canadian standards — and the Canadian (NRCan) zone system is not identical to the USDA number of the same value: it weighs summer heat, snow cover, wind and frost-free days, not just winter minimum. A cultivar sold as "hardy" in the US Midwest may still winterkill on the Canadian Prairies. Always select by your NRCan zone from planthardiness.gc.ca.
Is this data free to cite?
Yes. The compiled table is free to use with attribution to GrowersGuide.ca and a link to this page. Where a rating comes from a named Canadian breeding program (the Explorer/Parkland roses, Preston lilacs) or a specific breeder, please credit that primary source too.
How many cultivars and plant groups are covered?
The dataset currently rates 51 named cultivars across 9 plant groups — ginkgo, Japanese maple, dawn redwood, pawpaw, hydrangea, rose, lilac, clematis and magnolia — with more to be added. Each row lists the plant, cultivar, type, hardy-to zone (NRCan), a note, and the source.