Low temperatures can limit the choice of plants available to the cold climate gardener, but it is also desiccating winds that can pose further limitations, especially when looking for evergreens.

The following trees, conifers, shrubs, climbers, herbaceous

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

As well as plant lists, bear in mind the following when planning for cold climate gardening;

• Try to buy plants that have been raised in the conditions that they will be grown in. Buying from local growers if possible will be preferable to buying imported material
• Many plants are winter hardy – such as magnolias and camellias but their flowers are susceptible to spring frosts. Aim to choose selections that flower slightly later in the season (e.g. Camellia ‘Black Lace’), or even those that have a tendency to repeat flower such as M. soulangeana ‘Lennei’ or flower over a long period in spring and early summer – M. liliiflora ‘Nigra’ for example
• Bear in mind that microclimates exist within the general climate zone you are gardening in, as well as within the garden itself. Establishing shelterbelts and windbreaks may be useful to further increase the range of plants able to be grown

Hardiness ratings

Hardiness ratings, if available, for plants can help give some indication of plant hardiness. To be confident of full hardiness, opt for plants with ratings of H4 (old RHS system, as in RHS Plant Selector), H5-7 (new RHS system) or USDA Zones 1-8a.

Further reading

Sunset Western Garden Book edited by Kathleen N Brenzel (Sunset Publishing Corporation 2007, ISBN 978-0376039163)

The book is also made available through the RHS Lindley Library.

Some of the plants in the following list tolerate occasional temperatures down to at least -28°C (-18°F). All should tolerate temperatures of -9°C (15°F), not allowing for other environmental factors such as waterlogging.

Trees

Deciduous
Acer capillipes AGM, A. circinatum AGM, A. davidii, A. griseum AGM, A. pseudoplatanus, A. saccharinum AGM, A. tataricum subsp. ginnala AGM
Acer campestre – Native to GB 
Ailanthus altissima AGM
Amelanchier lamarckii AGM
Betula nigra AGM, B. pendula AGM – Native to GB and Ireland
Carpinus betulus – Native to GB
Celtis occidentalis
Crataegus laevigata – Native to GB  
Crataegus monogyna – Native to GB and Ireland
Fagus sylvatica (beech) AGM – Native to GB
Gymnocladus dioica
Laburnum
Liriodendron tulipifera AGM
Malus, including Malus sylvestris – Native to GB and Ireland
Morus alba, M. nigra AGM
Populus × canadensis ‘Robusta’, P. × canadensis ‘Aurea', P. tremula AGM – Native to GB and Ireland 
Prunus spinosa – Native to GB and Ireland
Prunus mume
Pyrus salicifolia ‘Pendula’ AGM
Quercus coccinea, Q. palustris AGM, Quercus petraea – Native to GB and Ireland 
Q. robur AGM – Native to GB and Ireland, Q. rubra AGM
Sorbus aria, S. aucuparia – Natives to GB and Ireland  
Tilia cordata AGM – Native to GB and Ireland, T. × euchlora AGM
Zelkova serrata AGM

Conifers
Calocedrus decurrens AGM
Ginkgo biloba AGM
Juniperus communis – Native to GB and Ireland
Juniperus virginiana
Larix decidua AGM, L. kaempferi AGM
Picea  breweriana AGM, P. omorika AGM, P. pungens
Pinus nigra AGM, P. ponderosa AGM, P. sylvestris AGM – Native to GB
Pseudotsuga menziesii AGM
Taxus baccata – Native to GB and Ireland
Taxus baccata ‘Fastigiata’ AGM – Cultivar of native to GB and Ireland
Thuja plicata
Tsuga canadensis
Xanthocyparis nootkatensis 'Green Arrow'

Shrubs

Evergreen
Calluna vulgaris – Native to GB and Ireland​ 
Erica cinerea – Native to GB and Ireland
Helianthemum nummularium – Native to GB and Ireland
Ilex aquifolium AGM – Native to GB and Ireland  
Mahonia aquifolium, M. japonica Bealei Group
Photinia villosa AGM
Rhododendrons such as R. 'Catawbiense Album’, ‘Nova Zembla’ and R. yakushimanum
Thymus pulegioides ‘Foxley’ – Cultivar of native to GB and Ireland
Thymus serpyllum L. – Native to GB
Ulex europaeus – Native to GB and Ireland 

Deciduous
Aronia arbutifolia
Buddleja davidii
Callicarpa bodinieri var. giraldii
Cornus sanguinea ‘Midwinter Fire’ – Cultivar of native to GB and Ireland
Calycanthus floridus
Camellia japonica
Caragana arborescens
Chaenomeles
Cornus mas AGM, C. sanguinea, C. stolonifera
Corylus avellana ‘Contorta’ AGM – Cultivar of native to GB and Ireland
Corylus maxima ‘Purpurea’ AGM 
Cotinus coggygria AGM
Cotoneaster
Cytisus scoparius 'Firefly' – Cultivar of native to GB and Ireland 
Deutzia
Elaeagnus angustifolia, E. commutata
Euonymus alatus AGM, E. europaeus – Native to GB and Ireland, E. fortunei 'Emerald 'n' Gold'
Euonymus europaeus ‘Red Cascade’ – Cultivar of native to GB and Ireland
Genista tinctoria – Native to GB
Hamamelis virginiana
Holodiscus discolor
Kerria japonica ‘Simplex’ and K. japonica ‘Pleniflora’ AGM 
Kolkwitzia amabilis
Ligustrum vulgare – Native to GB
Lonicera fragrantissima, L. involucrata, L. tatarica 'Hack's Red'
Mahonia aquifolium, M. japonica Bealei Group
Philadelphus coronarius and ‘Aureus’ AGM, P. 'Belle Etoile', P. ‘Virginal’AGM, P. ‘Beauclerk’
Potentilla fruticosa – Native to GB and Ireland 
R. typhina 
Rosa canina – Native to GB and Ireland, Rosa multiflora, R. spinosissima – Native to GB and Ireland,
R. rugosa, R. xanthina f. hugonis AGM
Rubus 'Golden Vale' AGM
Sambucus nigra – Native to GB and Ireland
Sambucus nigra f. porphyrophylla 'Gerda' AGM – Cultivar of native to GB and Ireland 
Spiraea
Symphoricarpos
Syringa vulgaris (lilac)
Viburnum × carlcephalum AGM, V. carlesii, V. lantana – Native to GB, V. opulus – Native to GB, Viburnum opulus ‘Roseum’ AGM – Cultivar of Native to GB and Ireland V. plicatum

Weigela

Climbers and wall shrubs

Evergreen or semi-evergreen
Akebia quinata
Euonymus fortunei ‘Coloratus’, E. fortunei ‘Silver Queen’ AGM)
Hedera helix (common ivy) – Cultivar of native to GB and Ireland, H. hibernica AGM – Cultivar of native to GB and Ireland 
Hedera helix 'Glacier' AGM – Cultivar of native to GB and Ireland
Kalmia latifolia AGM
Photinia villosa AGM
Pyracantha
Viburnum × burkwoodii

Deciduous
Ampelopsis brevipeduculata 'Elegans'
Aristolochia macrophylla
Celastrus orbiculatus
Clematis (deciduous kinds)
Fallopia baldschuanica  (syn. Polygonum baldschuanicum)
Humulus lupulus ‘Aureus’ AGM  – Cultivar of native to GB and Ireland 
Hydrangea anomala subsp. petiolaris AGM
Lonicera periclymenum 'Graham Thomas' AGM – Cultivar of native to GB and Ireland
Lonicera periclymenum 'Serotina' – Cultivar of native to GB and Ireland 
Parthenocissus quinquefolia AGM, P. tricuspidata AGM, and P. tricuspidata ‘Veitchii’ AGM
Wisteria (but some risk of flower bud damage in cold, late springs)

Ground cover

Evergreen and semi-evergreen
Arctostaphylos uva-ursi – Native to GB and Ireland 
Cotoneaster dammeri AGM
Epimedium × perralchicum AGM, E. × rubrum AGM
Euonymus fortunei ‘Coloratus’, ‘Emerald ‘n’ Gold’ AGM, ‘Silver Queen’ 
Mahonia aquifolium 'Apollo', M. repens
Pachysandra terminalis AGM
Taxus baccata ‘Repandens’ AGM – Cultivar of native to GB and Ireland
Thymus pulegioides – Native to GB and Ireland
Thymus serpyllum 'Pink Chintz' AGM – Cultivar of native to GB
Vinca minor – Native to GB and Ireland - Archaeophyte
Vinca minor 'Bowles's Variety' AGM – Cultivar of native to GB and Ireland - Archaeophyte

Deciduous
Cornus canadensis AGM
Epimedium perralderianum
Lysimachia nummularia ‘Aurea’ AGM – Cultivar of native to GB and Ireland
Potentilla fruticosa ‘Beesii’ AGM – Cultivar of native to GB and Ireland, P. ‘Longacre Variety’ AGM, P. ‘Manchu’

Herbaceous perennials (including a few alpine species)
Achillea, including Achillea millefolium ‘Red Velvet’ – Cultivar of native to GB and Ireland and Achillea ptarmica 'The Pearl' - Cultivar of native to GB and Ireland 
Aconitum carmichaelii, A. napellus
Ajuga reptans ‘Black Scallop’ – Cultivar of native to GB and Ireland
Alyssum montanum
Androsace
Anemone blanda AGM, A. × hybrida
Aquilegia including Aquilegia vulgaris – Native to GB and Ireland
Arabis including Arabis alpina subsp. caucasica 'Flore Pleno' AGM – Cultivar of native to GB
Aster 
Aubrieta 
Aurinia saxatilis  AGM 
Baptisia australis AGM 
Bergenia 
Campanula including Campanula rotundifolia – Native to GB and Ireland
Catananche caerulea 
Convallaria majalis AGM – Native to GB
Coreopsis grandiflora 
Cota tinctoria
Dianthus, including Dianthus deltoides AGM and Dianthus gratianopolitanus AGM – both native to GB 
Dicentra 
Digitalis, including Digitalis purpurea – Native to GB and Ireland
Doronicum 
Dryas octopetala AGM – Native to GB and Ireland 
Duchesnea indica 
Epimedium 
Festuca glauca 
Gaillardia × grandiflora 
Gentiana 
Geranium dalmaticum AGM, G. endressii AGM,G. macrorrhizum, G. pratense – Native to GB and Ireland, G. sanguineum – Native to GB and Ireland
Geranium sanguineum var. striatum AGM – Variety of native to GB and Ireland 
Geranium pratense ‘Mrs Kendall Clark’ AGM – Cultivar of native to GB and Ireland
Geum, including Geum rivale – Native to GB and Ireland
Gypsophila paniculata, G. repens AGM 
Helianthus salicifolius
Hemerocallis 
Hepatica
Heuchera sanguinea
Hosta
Hylotelephium spectabile AGM
Hyssopus officinalis
Iberis sempervirens AGM
Iris (bearded group, I. foetidissima AGM – Native to GB, I. sibirica AGM, I. unguicularis AGM)
Leucanthemum × superbum 
Leucanthemum vulgare – Native to GB and Ireland
Liatris spicata
Melissa officinalis
Nepeta
Oenothera macrocarpa AGM
Paeonia
Papaver nudicaule, P. orientale
Phlox divaricata AGM, P. paniculata, P. subulata
Platycodon grandiflorus AGM, P. grandiflorus ‘Mariesii’ AGM
Polemonium caeruleum
Primula (except greenhouse species)
Pulmonaria
Pulsatilla vulgaris AGM  
Rudbeckia laciniata
Sanguisorba officinalis – Native to GB and Ireland 
Saxifraga
Scabiosa caucasica
Scabiosa columbaria – Native to GB
Sedum telephium
Solidago
Stokesia laevis
Tanacetum parthenium – Native to GB and Ireland - Archaeophyte, T. vulgare – Native to GB 
Thymus
Trollius including Trollius europaeus – Native to GB and Ireland 
Veronica
Viola odorata – Native to GB and Ireland 

Bulbous and tuberous plants
Anemone
Crocus
Eranthis
Erythronium
Galanthus
Hyacinthoides non-scripta – Native to GB and Ireland
Hyacinthoides non-scripta 'Alba' – Cultivar of native to GB and Ireland 
Lilium
Muscari
Narcissus
Scilla autumnalis – Native to GB
Tulipa

Links

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