Introduction

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 and ground covering plants offer some useful suggestions.

Practical considerations

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.

Suitable plants

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
Ailanthus altissima AGM
Amelanchier lamarckii AGM
Betula nigra AGM, B. pendula AGM
Celtis occidentalis
Crataegus monogyna
Fagus sylvatica (beech) AGM
Fraxinus excelsior (ash) AGM
Gymnocladus dioica
Laburnum
Liriodendron tulipifera AGM
Malus
Morus alba, M. nigra AGM
Populus × canadensis ‘Robusta’, P. × canadensis ‘Serotina’, P. tremula AGM
Prunus mume
Pyrus salicifolia ‘Pendula’ AGM
Quercus coccinea, Q. palustrisAGM, Q. robur AGM, Q. rubra AGM
Sorbus aria, S. aucuparia
Tilia cordata AGM, T. × euchlora AGM
Zelkova serrata AGM

Conifers
Calocedrus decurrens AGM
Chamaecyparis nootkatensis
Ginkgo biloba AGM
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
Pseudotsuga menziesii AGM
Thuja plicata
Tsuga canadensis

Shrubs

Evergreen
Mahonia aquifolium, M. japonica Bealei Group
Photinia villosa AGM
Rhododendrons such as R. ’Catawbiense Album’, ‘Nova Zembla’ and R. yakushimanum

Deciduous
Aronia arbutifolia
Buddleja davidii
Callicarpa bodinieri var. giraldii
Calycanthus floridus
Camellia japonica
Caragana arborescens
Chaenomeles
Cornus mas AGM, C. sanguinea, C. stolonifera
Corylus avellana ‘Contorta’ AGM, C. maxima ‘Purpurea’ AGM
Cotinus coggygria AGM
Cotoneaster
Deutzia
Elaeagnus angustifolia, E. commutata
Euonymus alatus AGM, E. europaeus, E. fortunei
Hamamelis virginiana
Holodiscus discolor
Kerria japonica ‘Simplex’ and K. japonica ‘Pleniflora’ AGM
Kolkwitzia amabilis
Lonicera fragrantissima, L. involucrata, L. tatarica
Mahonia aquifolium, M. japonica Bealei Group
Philadelphus coronarius and ‘Aureus’ AGM, P. × lemoinei, P. ‘Virginal’AGM, P. ‘Enchantment’
Potentilla fruticosa
Rhus glabra, R. typhina AGM
Rosa multiflora, R. pimpinellifolia, R. rugosa, R. xanthina f. hugonis AGM
Rubus deliciosus
Spiraea
Symphoricarpos
Syringa vulgaris (lilac)
Viburnum × carlcephalum AGM, V. carlesii, V. lantana, V. opulus, 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), H. hibernica AGM
Kalmia latifolia AGM
Photinia villosa AGM
Pyracantha
Viburnum × burkwoodii

Deciduous
Ampelopsis glandulosa var. brevipedunculata
Aristolochia macrophylla
Celastrus orbiculatus
Clematis (deciduous kinds)
Fallopia baldschuanica AGM (syn. Polygonum baldschuanicum)
Humulus lupulus ‘Aureus’ AGM
Hydrangea anomala subsp. petiolaris AGM
Parthenocissus quinquefolia AGM, P. tricuspidata AGM, and P. tricuspidata ‘Veitchii’
Wisteria (but some risk of flower bud damage in cold, late springs)

Ground cover

Evergreen and semi-evergreen
Arctostaphylos uva-ursi
Cotoneaster dammeri AGM
Epimedium × perralchicum AGM, E. × rubrum AGM
Euonymus fortunei ‘Coloratus’, ‘Emerald ‘n’ Gold’ AGM, ‘Silver Queen’ AGM
Mahonia aquifolium, M. repens
Pachysandra terminalis AGM
Taxus baccata ‘Repandens’ AGM

Deciduous
Cornus canadensis AGM
Epimedium perralderianum
Lysimachia nummularia ‘Aurea’ AGM
Paxistima canbyi
Potentilla fruticosa ‘Beesii’ AGM, P. ‘Longacre Variety’ AGM, P. ‘Manchu’

Herbaceous perennials (including a few alpine species)
Achillea
Aconitum carmichaelii, A. napellus
Alyssum montanum
Androsace
Anemone blanda AGM, A. × hybrida
Anthemis tinctoria
Aquilegia
Arabis
Aster 
Aubrieta 
Aurinia saxatilis  AGM 
Baptisia australis AGM 
Bergenia 
Campanula 
Catananche caerulea 
Convallaria majalis AGM 
Coreopsis grandiflora 
Dianthus 
Dicentra 
Digitalis 
Doronicum 
Dryas octopetala AGM 
Duchesnea indica 
Epimedium 
Festuca glauca 
Gaillardia × grandiflora 
Gentiana 
Geranium dalmaticum AGM, G. endressii AGM,G. macrorrhizum, G. pratense, G. sanguineum
Geum 
Gypsophila paniculata, G. repens AGM 
Helianthus multiflorus 
Hemerocallis 
Hepatica
Heuchera sanguinea
Hosta
Hyssopus officinalis
Iberis sempervirens AGM
Iris (bearded group, I. foetidissima AGM, I. sibirica AGM, I. unguicularis AGM)
Leucanthemum × superbum
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
Saxifraga
Scabiosa caucasica
Sedum spectabile AGM, S. telephium
Solidago
Stokesia laevis
Tanacetum parthenium, T. vulgare
Thymus
Trollius
Veronica
Viola odorata

Bulbous and tuberous plants
Anemone
Crocus
Eranthis
Erythronium
Galanthus
Lilium
Muscari
Narcissus
Tulipa

Links

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