Computer-Aided Plant Selection, Adapted Landscape Trees for ...

Special Publication-06-24
A Contribution to the Series:
COMPUTER-AIDED PLANT SELECTION
ADAPTED LANDSCAPE TREES FOR NORTHEASTERN NEVADA
USDA PLANT HARDINESS ZONE 6
Jay Paxson, Extension Educator, Elko County
USDA Plant Hardiness Zone 6 (A & B):
Average winter low temperatures from -10° F
to 0°F. Characteristic U. S. cities: St. Louis,
Missouri; Lebanon, Pennsylvania;
McMinnville, Tennessee; Branson, Missouri;
Lebanon, Missouri; extensive portions of
Central and Northwest Nevada. 1
A New Plant Selection Technology for
Gardeners and the Green Industry
In recent years, computer programs have
been developed to assist the gardening public
with the task of species selection. A premier
example of this new technology is SelecTree -
A Tree Selection Guide, maintained by the
Urban Forest Ecosystems Institute (UFEI) at
California Polytechnic State University (Cal
Poly), San Luis Obispo, California. It is an
interactive program designed to match specific
tree species to particular sites based on
compatible characteristics. It is funded by the
California Department of Forestry and Fire
Protection through the Urban and Community
Forest Funds. SelecTree presently searches a
database of 1,481 trees and provides 49
selection criteria. Cal Poly cautions gardeners
that, “Lists of trees generated by SelecTree
should be viewed as a guide, not as the final
authority in tree selection.” 2
http://selectree.calpoly.edu/
The SelecTree program has the ability to
manage a large number of attributes. The
greater the number of attributes selected, the
smaller the output will be. In the case of this
study, the 224 species and cultivars that follow
were generated by the SelecTree program
based on only five attributes. The selected
attributes utilized in this search are: USDA
Hardiness Zone: “6 (‘A’ + ‘B’)”; Exposure “Full
Sun”; Soil Moisture “Moist”; Soil Texture
“Clay”; and Soil pH “Slightly Alkaline”. 2 The
results are as follows:
COMMON NAME SCIENTIFIC NAME CULTIVAR USDA ZONE SUNSET ZONE
Trident maple Acer buergeranum 4-9 2-9; 14-17; 20-21
Hedge maple Acer campestre 4-8 1-9; 14
Japanese snakebark maple
Acer capillipes 5-7 3-9; 12; 14-24; 30-34; 39
Monroe vine maple
Cut-leaf vine maple Acer circinatum 'Monroe' 5-9 1-6; 14-17
Amur maple Acer ginnala 3-9 2-9; 14-17; 20-21
Flame amur maple Acer ginnala 'Flame' 3-9 1-9; 14-16
Norway maple Acer platanoides 3-7 1-9; 14-17

Cleveland maple Acer platanoides 'Cleveland' 4-7 1-9; 14-17
Columnare maple Acer platanoides 'Columnare' 4-7 1-9; 14-17
Emerald Queen maple Acer platanoides 'Emerald' 4-7 1-9; 14-17
Summer Shade maple Acer platanoides 'Summer Shade' 4-7 1-9; 14-17
Red maple Acer rubrum 3-9 1-9; 14-17
Autumn Flame red maple Acer rubrum 'Autumn Flame' 4-8 1-9; 14-17
Columnar red maple Acer rubrum 'Columnare' 3-9 1-9; 14-17
Gerling red maple Acer rubrum 'Ferling' 4-8 1-9; 14-17
Red Sunset red maple Acer rubrum 'Red Sunset' 4-8 1-9; 14-17
Silver maple Acer saccharinum 3-8 1-9; 12; 14-24
Sugar maple Acer saccharum 3-8 1-10; 14-20
Green Mountain sugar maple Acer saccharum 'Green Mountain' 3-8 1-10; 14-20
Newton Sentry sugar maple Acer saccharum 'Newton Sentry' 3-8 1-10; 14-20
Temple's Upright sugar maple Acer saccharum 'Temple's Upright' 3-8 1-10; 14-20
Red horsechestnut Aesculus carnea 4-9 1-10; 12; 14-17
Briottii red horsechestnut Aesculus carnea 'Briottii' 3-7 1-10; 12; 14-17
Common horsechestnut Aesculus hippocastanum 4-7 1-10; 14; 14-17
Tree-of-Heaven Ailanthus altissima 4-8 1-24
Silk tree Albizia julibrissin 6-10 4-23
Silk tree Albizia julibrissin 'Rosea' 6-10 4-23
Italian alder Alnus cordata 5-9 8-9; 12-24
Black alder Alnus glutinosa 3-7 1-10; 14-24
Japanese angelica Aralia elata / A. chinensis 3-8 1-10; 14-24
Devil's walking stick Aralia spinosa 4-9 2-24
Pawpaw / Custard apple
Asimina triloba 5-8 2-9; 14; 18-21; 28-41
European white birch Betula pendula 3-6 1-12; 14-24
Japanese white birch Betula platyphylla japonica 4-7 1-11; 14-24
Paper mulberry Broussonetia papyrifera 6-11 3-24
Incense cedar Calocedrus decurrens 5-8 1-12; 14-24
Colossal chestnut
Sweet chestnut Castanea 'Colossal' 4-8 1-9; 14-17
Spanish chestnut Castanea sativa 4-11 1-9; 14-17
Common catalpa Catalpa bignonioides 5-9 1-24
Western catalpa Catalpa speciosa 4-8 1-24
Cedar of Lebanon Cedrus libani 5-8 3-10; 14-24
Sugar hackberry Celtis laevigata 5-9 2-20
Cyprus cedar / Cyprian cedar Cedrus brevifolia 5-8 5-24; 32
Common hackberry Celtis occidentalis 3-9 1-24
Eastern redbud Cercis canadensis 4-9 1-24
White eastern redbud Cercis canadensis 'Alba' 4-9 1-24
Purple-leaf eastern redbud Cercis canadensis 'Forest Pansy' 4-9 1-24
Western redbud Cercis occidentalis 4-9 1-24
Judas tree Cercis silaquastrum 5-9 3-19
Chinese fringe tree Chionanthus retusus 3-9 2-9; 14-24

Giant dogwood Cornus controversa 5-8 3-9; 14; 18-19
Autumn Glory hawthorn Crataegus 'Autumn Glory' 4-7 A-2; A-3; 2-12; 14-17
Toba hawthorn Crataegus 'toba' 'Toba' 4-7 A-3; 1-10
Cockspur thorn Crataegus crus-galli 3-7 1-11; 14-17
English hawthorn Crataegus laevigata 'Crimson Cloud' 4-8 1-11; 14-17
Paul's Scarlet English
hawthorn Crataegus laevigata 'Paul's Scarlet' 4-8 2-12; 14-17
Carriere hawthorn Crataegus lavallei 4-7 3-12; 14-21
Washington hawthorn Crataegus phaenopyrum /
Crataegus cordata 4-8 3-12; 14-17
Japanese cryptomeria Cryptomeria japonica 6-9 4-9; 14-24
Plume cryptomeria Cryptomeria japonica 'Elegans' 6-9 4-9; 14-24
Leyland cypress Cupressocyparis leylandii 6-10 3-24
Naylor's Blue Leyland cypress Cupressocyparis leylandii 'Naylor's Blue' 6-10 3-24
Atlas broom Cytisus battandieri 5-8 5-6
Quince Cydonia oblonga 5-8 1-21
American persimmon Diospyros virginiana 4-9 3-9; 14-16; 18-23
Russian olive Elaeagnus angustifolia 3-8 1-3; 7-14; 18-19
Silverberry Elaeagnus pungens 6-10 4-24
Evergreen euonymus Euonymus japonicus 5-11 4-13; 18-20
American beech Fagus grandifolia 3-8 1-6
European beech Fagus sylvatica 4-7 2-9; 14-21
White ash Fraxinus americana 3-9 1-11; 14-17
'Autumn
Applause' 4-9 1-11; 14-17
Autumn Applause white ash Fraxinus americana
European ash Fraxinus excelsior 5-8 7-24
Holotricha ash Fraxinus holotricha 6-9 4-24
Flowering ash Fraxinus ornus 6-9 3-9; 14-17
Raywood ash Fraxinus oxycarpa 'Raywood' 5-8 7-24
Marshall Seedless green ash Fraxinus pennsylvanica 'Marshall' 3-8 1-6
Summitt green ash Fraxinus pennsylvanica 'Summitt' 3-8 1-6
Green ash / red ash Fraxinus pennsylvanica 3-9 1-6
Mt. Aetna broom Genista aethnensis 6-7 4-9; 12-22
Maidenhair tree Ginkgo biloba 3-8 1-10; 12; 14-24
Autumn Gold maidenhair tree Ginkgo biloba 'Autumn Gold' 3-8 1-10; 12; 14-24
Fairmont maidenhair tree Ginkgo biloba 'Fairmont' 3-8 1-10; 12; 14-24
Imperial honey locust Gleditsia triacanthos inermis 'Imperial' 4-8 1-16; 18-20
Kentucky coffee tree Gymnocladus dioica 3-8 1-3;7-10; 12-16; 18-21
Rose of Sharon Hibiscus syriacus 5-10 1-21
Japanese raisin tree Hovenia dulcis 6-10 1-9; 14-24
Idesia Idesia polycarpa 6-8 4-9; 14-24
English walnut Juglans regia 5-9 1-9; 14-23
English holly Ilex aquifolium 5-9 4-9; 12-24
American holly Ilex opaca 5-9 2-9; 15-16; 20-23
Perny holly Ilex pernyi 7-10 4-9; 14-24
Chinese juniper Juniperus chinensis 4-9 1-24

Hollywood juniper Juniperus chinensis 'Torulosa' 4-11 1-24
Rocky Mountain juniper Juniperus scopulorum several varieties 4-9 1-24
Eastern red cedar Juniperus virginiana 2-9 1-24
Goldenrain tree Koelreuteria paniculata 5-9 2-21
Kew goldenrain tree Koelreuteria paniculata 'Kew' 5-9 2-21
European larch Larix decidua 3-6 1-9; 14-17
Japanese larch Larix kaempferi 4-7 1-9; 14-19
Western larch Larix occidentalis 4-7 A-3; 1-7
California privet Ligustrum ovalifolium 5-9 4-24
American sweetgum Liquidambar styraciflua 3-8 1-9; 14-24
Burgundy sweetgum Liquidambar styraciflua 'Burgundy' 3-8 1-9; 14-24
Palo Alto sweetgum Liquidambar styraciflua 'Palo Alto' 3-8 1-9;14-24
Tulip tree Liriodendron tulipifera 5-9 1-10;14-23
Osage-orange Maclura pomifera 5-9 1-24
Victoria magnolia Magnolia grandiflora 'Victoria' 6-10 4-12; 14-24
Kobus magnolia Magnolia kobus 'Wada's Memory' 5-8 1-9; 14-24
Purple lily magnolia Magnolia liliflora 'Nigra' 5-8 2-9; 14-24
Lily magnolia Magnolia liliflora 5-8 2-9; 14-24
Merrill magnolia Magnolia loebneri 'Merrill' 4-9 2-9; 14-24
Else Frye magnolia Magnolia salicifolia 'Else Frye' 4-9 2-9; 14-21
Saucer magnolia Magnolia soulangiana 5-9 1-10; 14-24
Alba saucer magnolia Magnolia soulangiana 'Alba' 5-9 2-9; 14-24
Burgundy saucer magnolia Magnolia soulangiana 'Burgundy' 5-9 2-9; 14-24
Lilliputian saucer magnolia Magnolia soulangiana 'Lilliputian' 5-9 2-9; 14-24
San Jose saucer magnolia Magnolia soulangiana 'San Jose' 5-9 2-9; 14-24
Star magnolia Magnolia stellata several varieties 5-9 1-9; 14-24
Watson magnolia Magnolia watsonii 5-9 4-9; 14-24
Hopa crabapple Malus x 'hopa' 4-8 1-11; 14-24
Red Jade crabapple Malus x 'red jade' 3-8 1-11; 14-24
Arnold crabapple Malus arnoldiana 3-8 1-11; 14-24
Carmine crabapple Malus atrosanguinea 3-8 1-11; 14-24
Columnar crabapple Malus baccata 'Columnaris' 3-8 1-11; 14-21
Japanese flowering crabapple Malus floribunda 4-7 1-11; 14-21
Red Jewel crabapple Malus floribunda 'Red Jewel' 4-7 1-11; 14-21
Tea crabapple Malus hupehensis 4-8 1-11; 14-21
Dawn redwood
Metasequoia
glyptostroboides 5-8 3-24
White mulberry Morus alba 3-9 1-24
Sour gum Nyssa sylvatica 4-9 2-10; 14-21
Holly osmanthus Osmanthus heterophyllus 'Ilicifolius' 6-9 3-10; 14-24
European hop hornbeam Ostrya carpinifolia 4-8 3-9; 14-17
American hop hornbeam Ostrya virginiana 3-9 1-9; 14-17; 28; 31-43
Empress tree Paulownia tomentosa 5-9 1-24
Amur corktree Phellodendron amurense 3-8 1-9; 14-24
Norway spruce Picea abies 2-7 1-6; 14-17

Englemann spruce Picea engelmannii 2-5 1-6; 14-17
White spruce Picea glauca 2-6 1-6; 14-17
Oriental spruce Picea orientalis 4-7 2-9; 14-17; 32-41
Colorado spruce Picea pungens 4-7 1-10; 14-17
Sitka spruce Picea sitchensis 6-8 4-6; 14-17
Lacebark pine Pinus bungeana 4-8 1-9; 12-24
Mexican pinyon pine Pinus cembroides 5-8 n/a
Japanese red pine Pinus densiflora 3-7 4-9; 14-24
Tanyosho pine Pinus densiflora 'Umbraculifera' 3-7 4-9; 14-21
Mondell pine Pinus eldarica 6-9 4-24
Limber pine Pinus flexilis 4-7 1-11; 14-21; 32-43
Singleleaf pinyon pine Pinus monophylla 6-8 1-24
Austrian black pine Pinus nigra 5-8 2-12; 14-21; 32-41
Japanese white pine Pinus parviflora 4-7 2-9 ;14-24
Table mountain pine Pinus pungens 6-8 5-9; 14-17
White pine Pinus strobus 3-7 1-9; 14-24
Scotch pine Pinus sylvestris 3-8 1-7; 14-24
Japanese black pine Pinus thunbergiana 6-8 1-8; 14-24
Chinese pistache Pistacia chinensis 6-9 4-16; 18-23
London plane tree Platanus acerifolia 5-8 2-24; 31-41
Bloodgood London plane tree Platanus acerifolia 'Bloodgood' 4-9 2-24
American sycamore Platanus occidentalis 4-9 1-24
Beverly Hills arborvitae Platycladus orientalis 'Beverlyensis' 4-9 1-24
White poplar Populus alba 4-9 1-24
Bolleana poplar Populus alba 'Pyramidalis' 3-8 1-24
Lombardy poplar Populus nigra 'Italica' 3-9 1-24
Pyramidal Simon poplar Populus simonii 'Fastigiata' 2-5 1-24
Accolade cherry Prunus 'Acolade' 4-8 2-9; 14-17
Flowering plum Prunus blireiana 5-9 3-22; 32-34 ;39
Purple-leaf / Pissard plum Prunus cerasifera 'Atropurpurea' 5-8 3-22; 28; 31-34; 39
Newport purple-leaf plum Prunus cerasifera 'Newport' 4-8 2-22
Thundercloud purple-leaf plum
Thundercloud cherry plum Prunus cerasifera 'Thundercloud' 5-8 3-22; 28; 31-34; 39
Sour cherry Prunus cerasus 3-8 1-3; 5-11; 14-16
English laurel Prunus laurocerasus 6-9 4-9; 14-24
Amur chokecherry Prunus maacki 2-6 1-3; 10
Japanese Flowering Apricot Prunus mume 6-8 2-9; 12-22
Peach Prunus persica 5-8 2-24
Sargent cherry Prunus sargentii 5-8 1-7; 14-17
Birch bark cherry
Paperbark cherry Prunus serrula 5-6 1-7; 14-16
Kwansan Japanese flowering
cherry Prunus serrulata 5-6 2-7; 14-20
Kwansan Japanese flowering
cherry Prunus serrulata 'Kanzan' 5-6
2-7; 14-20

Kwansan Japanese flowering
cherry Prunus sekiyarn 'Kwanzan' 5-6 2-7; 14-20
Autumn flowering cherry Prunus subhirtella 'Autumnalis' 5-8 2-7; 14-20
Weeping Higan cherry Prunus subhirtella 'Pendula' 5-8 2-7; 14-20
Western chokecherry Prunus virginiana 3-8 1-3; 10
Akebono flowering cherry
Daybreak Yoshino cherry Prunus yedoensis 'Akebono' 5-8 2-7; 14-20
Yoshino flowering cherry
Potomac flowering cherry Prunus yedoensis 5-8 2-7; 14-20
Douglas-fir Pseudotsuga menziesii 5-6 2-7; 10; 14-17; 34-41
Chinese wingnut Pterocarya stenoptera 6-11 5-24
Lalandei pyracantha Pyracantha coccinea 'Lalandei' 6-9 2-24
Flowering ornamental pear Pyrus calleryana 5-9 2-9; 14-21; 28; 31-41
Aristocrat flowering pear Pyrus calleryana 'Aristocrat' 5-9 2-9; 14-21; 28; 31-41
Bradford pear Pyrus calleryana 'Bradford' 5-9 2-9; 14-21; 28; 31-41
Redspire ornamental pear Pyrus calleryana 'Redspire' 5-9 2-9; 14-21; 28; 31-41
Common pear Pyrus communis 4-8 2-9; 14-21; 28; 31-41
Sawtooth oak Quercus acutissima 5-9 2-7; 29-41
Swamp white oak Quercus bicolor 4-8 1-3; 10
Scarlet oak Quercus coccinea 4-9 2-24; 31-41
Oregon white oak Quercus garryana 6-9 4-6; 15-17
Bur oak / mossy cup oak Quercus macrocarpa 3-8 1-11; 14-24; 29-45
Pin oak Quercus palustris 4-8 1-24
Willow oak Quercus phellos 6-9 1-4; 6-16; 18-21
Red oak
Northern red oak Quercus rubra 5-8 1-12; 14-24; 31-45
4-9; 12; 14-17; 26; 28-45;
Shumard red oak Quercus shumardii 5-9
37; 39
Tallhedge / alder buckthorn
Glossy buckthorn Rhamnus frangula 'Rolumaris' 3-7 1-7; 10-11; 32-45
Staghorn sumac Rhus typhina 3-9 1-10; 14-17
Idaho locust
'Idahoensis'
Robinia ambigua
4-8 1-24
Black locust Robinia pseudoacacia 4-8 1-24
Salix alba tristis /
Golden weeping willow S. babylonica aurea 4-8 1-24
Weeping willow Salix babylonica 4-8 1-24
Wisconsin weeping willow Salix blanda 5-9 2-24; 30-41
Hankow / corkscrew willow
Curly willow / Pekin willow Salix matsudana 4-8 3-24; 30-34; 39
Twisted Hankow willow Salix matsudana 'Tortuosa' 4-8 3-24; 30-34; 39
Giant sequoia Sequoiadendron giganteum 5-9 1-24
Japanese pagoda tree /
Chinese scholar tree Sophora japonica 5-8 2-24; 31-41
Korean mountain-ash Sorbus alnifolia 4-7 1-10; 14-17
European mountain-ash Sorbus aucuparia 3-6 1-10; 14-17
Japanese lilac Syringa reticulata 4-7 1-12; 14-16
Common lilac Syringa vulgaris 3-7 1-11

Bald cypress Taxodium distichum 4-9 2-10; 12-24; 26; 28-43
Montezuma bald cypress Taxodium mucronatum 6-11 5-6; 8-10; 12-14
English yew Taxus baccata 5-7 3-9; 14-24; 32-33
American arborvitae Thuja occidentalis 2-7 2-9; 15-17; 21-24
Western red cedar Thuja plicata 4-8 1-9; 14-24
American linden Tilia americana 3-8 1-17
Littleleaf linden Tilia cordata 4-7 1-17
Greeenspire littleleaf linden Tilia cordata ‘Greenspire’ 3-7 1-17
June Bride Littleleaf linden Tilia cordata ‘June Bride’ 3-7 1-17
Rancho littleleaf linden Tilia cordata ‘Rancho’ 4-7 1-17
Crimean linden Tilia euchlora 3-8 1-17
American elm Ulmus americana 2-9 1-11; 14-21
Smooth-leaf elm Ulmus carpinifolia 5-7 2-11; 14-21; 31-41
Drake Chinese elm Ulmus parvifolia ‘Drake’ 5-10 3-24; 26-35; 37-39
Siberian elm Ulmus pumila 5-9 1-24; 26-45
Japanese snowball Viburnum plicatum 5-9 3-9; 14-24; 31-35; 37; 39
Blackhaw Viburnum prunifolium 3-9 1-9; 14-21
Chaste tree Vitex agnus-castus 6-10 4-24
Sawleaf zelkova Zelkova serrata 5-8 3-21; 28-35; 37; 39
Chinese jujube Ziziphus jujuba 6-9 7-16; 18-24
Interestingly, a large number of tree
species and cultivars that are widely
recognized locally as good performers in
USDA Zones 4 and 5 were omitted from this
SelecTree output for Zone 6. In most cases,
plants adapted to Zones 4 or 5 should perform
well in Zone 6 because Zone 6 represents a
less harsh environment. In an effort to ensure
that this study represents a reasonably
comprehensive list of adapted tree species and
cultivars for Zone 6, additional plants are
included in the supplemental list below. Plant
species are listed only if they satisfy two
criteria: 1) recommendation in at least two
regional publications 2,3,4,5,6,7,8,9,10 and 2)
recognized adaptation to USDA Hardiness
Zone 6. Hardiness of plants was checked
against two comprehensive industry and
Internet standards: Dave’s Garden website 4
and Edward Gilman and Dennis Watson’s “680
Tree Fact Sheets” Web pages at the University
of Florida. 13
Twenty-eight species and cultivars are
listed. Even when the SelecTree-generated list
and those below are combined, they should not
be considered exhaustive. As a rule of thumb,
the more times a species is listed in the
literature, the more it has been studied, and the
more likely it can be relied upon to be
successful in a particular area. Some plants,
even though listed in the SelecTree list, the
supplemental list, and many other lists, simply
may not perform well on your site. Microclimate
may play a very large role at your location.
Also, some plants listed below may be poor
performers because they are disease-prone or
poorly adapted. They may also be weedy or
invasive. A little local research is strongly
urged to ensure that the tree you have chosen
has been successfully grown in your area. The
reasons for failure can often be attributed to
cultural conditions, but in our region, the
problem is often a matter of soils and/or
marginal hardiness (i.e., poorly or barely
adapted to the conditions of a given area).

SUPPLEMENTAL LIST FROM THE LITERATURE
Adapted Tree Species
Common Name
Scientific Name
White fir
Abies concolor
Rocky Mountain maple
Acer glabrum
Boxelder
Acer negundo
Globe Norway maple
Acer platanoides ‘Globosum’
Redfruited tree-of-Heaven
Ailanthus altissima ‘Erythrocarpa’
Hawthorn
Crataegus spp
Black hawthorn
Crataegus douglasii
Red King Russian olive
Eleagnus angustifolia ‘Red King’
Blue ash
Fraxinus quadrangulata
Honeylocust
Gleditsia triacanthos
Thornless honeylocust
Gleditsia triacanthos var. inermis
Redberry juniper
Juniperus monosperma
Western juniper
Juniperus occidentalis
Utah juniper
Juniperus osteosperma
Flowering crabapple
Malus hybrids
Bechtel crabapple
Malus ‘Bechtel’
Dolge crabapple
Malus ‘Dolge’
Dorothea crabapple
Malus ‘Dorothea’
Radiant crabapple
Malus ‘Radiant’
Colorado blue spruce
Picea pungens glauca
Lodgepole pine
Pinus contorta var. laitfolia
Pinyon pine
Pinus edulis
Bristlecone pine
Pinus longaeva
Mugo pine
Pinus mugo
Ponderosa pine
Pinus ponderosa
European bird cherry
Prunus padus
Chinkapin oak
Quercus muhlenbergii
Silverleaf buffaloberry
Shepherdia argentea
It must be understood that any listing of
plants, whether computer-aided or in print, is
not and cannot be exhaustive for any particular
area. It is in every gardener’s nature to wonder
if a particular plant species could be grown
where he or she lives. Thus, new trials take
place continuously, whether they are sciencebased
or informal. Professional horticulturists
continually search for, discover, and propagate
new species and cultivars, which then undergo
official and unofficial hardiness trials. The
SelecTree program may not be the ‘final
authority’ in plant selection, but it is a powerful
tool to help us determine which plants are most
likely to prosper where we live and garden.
APPENDIX: GARDENING IN NEVADA
The Hardiness Zone Systems
The three most commonly used plant
hardiness zone systems are the USDA’s Plant

Hardiness Zones 1 , Sunset Publishing
Corporation’s Climate Zones 11 , and the
American Horticultural Society’s (AHS) Heat-
Zones. 12 Each of these was developed using
long-term meteorological data and by applying
somewhat different criteria. For example, the
USDA Plant Hardiness Zone system consists
of 11 zones and 9 subdivisions and is based
on the average winter low temperatures that
occur within the respective zones. 1 The USDA
system covers the United States, Canada, and
Mexico.
The Sunset Publishing Corporation’s
Climate Zones (through their publications
Sunset Western Garden Book and the Sunset
National Garden Book) is composed of 45
Climate Zones of the United States together
with narrow slices of Canada and Mexico
where they adjoin at the international
boundary. 12 Sunset’s Climate Zone Map is
based on a complex set of factors that include
winter minimum temperatures, as well as
summer high temperatures, altitude, proximity
to seacoast or mountains, rainfall, relative
humidity, aridity, and the length of the growing
season. 11,12
Finally, the American Horticultural
Society’s system, the Plant-Heat Zone Map,
consists of 11 zones and is based on the
average number of days above 86°F—the
temperature at which certain cellular proteins
can be damaged in many plants. The AHS
system covers the continental United States,
plus Alaska and Hawaii. 13
In coordination with the respective
hardiness zone systems, plant materials of
every kind have been experimentally grown
over many years throughout North America to
determine their inherent hardiness. Today, new
species and cultivar introductions continuously
undergo extensive trials so that they can be
added to the growing databases. The result of
this long-term applied research can be found in
a great many plant reference books, gardening
books, and catalogs, as well as on
innumerable Internet sites dedicated to
horticulture. 1,2,11,12,13,14,15,16
The Art and Science of Gardening
Gardening has long been a pastime of
friends and neighbors sharing an enjoyable
and productive hobby. They traded lore, plant
divisions, hand-me-downs, and handharvested
seed. Generous gardeners often
‘potted-up’ desirable specimens for friends,
neighbors, and relatives. Travelers, while on
the road, saw attractive or interesting plants
and wondered if they might grow where they
lived. Whether plants were moved a single mile
or a thousand, they sometimes grew
spectacularly, but sometimes failed miserably.
To early gardeners, the art and science of
gardening must have seemed much more a
matter of trial-and-error than science. As the
country expanded westward, gardeners began
to recognize a critical and practical need: how
can I tell what plants can be reliably grown
here at home as well as elsewhere in the
country? Put another way, will plants from my
‘Aunt Mabel’s’ home in Connecticut grow here
in northeastern Nevada? Well, maybe.
Limitations of Environment
Environmental conditions can impose
severe limits on the success of plants. Many
factors could be listed, but among the most
important are soil moisture, soil pH, extremes
of temperature, and soil salinity. In
northeastern Nevada, all plants require
supplemental water during their establishment
period and most will require periodic watering
during periods of drought, high temperatures,
high winds, and even periodically during
autumn and winter. Excessively high or low pH
(relative acidity or alkalinity) can limit the
success of a great many plant species. For
instance, Vaccinium spp (blueberry) grow best
when soil pH is between 4.5 and 4.8 17 , while
other species, such as sagebrush (Artemisia
spp) can grow in soil with a pH as high as
10.0! 18 However, some plant species such as
green ash (Fraxinus pennsylvanica) are
capable of growing in a wide range of soil pH,
from 5.0 to 8.0. 19
Another limiting factor is extreme cold
and heat, either daily or seasonal. Tender

semi-tropical plants such as Hibiscus rosasinensis
(tropical hibiscus) cannot tolerate daily
temperatures that fall below 20°F, and
Philodendron bipinnatifidum (cut-leaf or tree
philodendron) cannot tolerate temperatures
that fall below 30°F. 20 On the other hand, as
with the effects of soils, some plants such as
spruce (Picea spp) and beech (Fagus spp) are
capable of good performance in a wide range
of temperatures that can include relatively hot
summers and very cold winters. Such
adaptable plants are known to have a large
climatic amplitude.
Soil salinity, the last in our group of
limiting environmental conditions, affects a
wide range of tree species. Certain species are
capable of tolerating relatively high salinity
levels. Others are capable of growing only in
low salinity soils. For instance, Norway maple
(Acer platanoides), honeylocust (Gleditsia
triacanthos), black locust (Robinia
pseudoacacia), and red oak (Quercus rubra)
are considered high tolerance species. Low
tolerance species include pin oak (Quercus
palustris), apple and crabapple cultivars (Malus
spp), silver maple (Acer saccharinum), and
American linden (Tilia americana). Extremes
of cold, heat, and salinity can limit the success
of many plants, making careful planning and
species selection essential.
The Place Where We Live: Weather vs.
Climate
equivalent, but they are related. Weather is the
state of the atmosphere at a given time and
place (i.e., a snapshot of the atmospheric
variables today or over the space of a few
days). 21 Climate, on the other hand, is the
weather averaged over a long period of time,
usually a minimum of 30 years. 22 In order for
plants to prosper, plant material selections for
garden, landscape, reclamation, agriculture,
and other applications must be well adapted to
the conditions where they are planted. Soils
can be improved, but little can be done to alter
climate. As a result, to be successful, we’re
obliged to adapt our gardening to suit our
particular set of climatic variables.
To ensure that the plants we place in
our garden and landscapes thrive, we try to
give them the best ‘home’ we can. We can
provide them with richly amended soil, macroand
micronutrients, adequate moisture, pest
control as required, proper pruning, and proper
placement in the landscape. But if the plants
are not adapted to the climate in which they’re
planted, they’re probably destined to wither
and die. Therefore, before we can begin, we
must know what to expect in terms of climate.
Fortunately, researchers have developed the
three major systems that map out the plant
hardiness zones of the United States, Canada,
and Mexico. Consulting any of these will help
us locate our home zone and provide us with a
basis for selecting plant materials having the
best chance of success in our area.
The terms ‘weather’ and ‘climate’ are
often used interchangeably. They are not
REFERENCES:
1
Cathey, Henry M. U. S. Department of Agriculture
Miscellaneous Publication No. 1475, “USDA Plant Hardiness
Zone Map.” 1990; Web version, March 1998, Revised March
2001, U.S. National Arboretum, Ramon Jordan, Ed. U. S.
Department of Agriculture, Agricultural Research Service, U. S.
National Arboretum, Washington, DC.
http://www.usna.usda.gov/Hardzone/ushzmap.html
2
Reimer, Jeffrey L. and Walter Mark. "SelecTree: A Tree
Selection Guide." http://selectree.calpoly.edu/ (Date Visited: 27
July, 2006).
3
Dietz, Tony. “Select Tree Species for Northeastern Nevada.”
Nevada Division of Forestry, Elko, NV. Sept. 2002.
4
Davis, Rodney L. “Commonly Planted Evergreens in Lander
County.” University of Nevada Cooperative Extension, Fact
Sheet 01-49.
5
Davis, Rodney L. “Commonly Planted Large Deciduous Trees
in Lander County.” University of Nevada Cooperative
Extension, Fact Sheet 01-50.
6
Davis, Rodney L. “Commonly Planted Small Deciduous Trees
in Lander County.” University of Nevada Cooperative
Extension, Fact Sheet 01-51.
7
Johnson, Wayne S and Jason Davison. “Deciduous Trees for
Northeast Nevada.” Informal Fact Sheet, University of Nevada
Cooperative Extension. Undated.
8
Johnson, Wayne S and John Balliette. “Hardy, Drought
Tolerant and Moderately Salt Tolerant Trees for Northern
Nevada.” University of Nevada Cooperative Extension, Special
Publication 88-73.
9
Johnson, Wayne S “Salt Tolerant Trees for Northeast
Nevada.” Informal Fact Sheet, University of Nevada
Cooperative Extension. Undated.

10
Johnson, Wayne S and Jay Davison. “Selected Evergreen
Trees for Elko, Nevada.” Informal Fact Sheet, University of
Nevada Cooperative Extension. Undated.
11
Brenzel, Norris Kathleen, Ed. “Western Garden Book.” 2001.
Sunset Publishing Corporation, Menlo Park, CA.
12
Eyre, Normand Suzanne, Ed. “Sunset National Garden
Book.” First Edition, 1997. Sunset Books Inc., Menlo Park, CA.
13
American Horticultural Society. “Plant Heat Zone Map.”
1990. http://www.ahs.org/pdfs/05_heat_map.pdf
14
Kuhns, Michael. “Trees of Utah and the Intermountain
West—A Guide to Identification and Use.” 1998. Utah State
University Press. Utah State University Extension, Logan, UT.
1 5 Gilman, Edward F. and Dennis G. Watson. “680 Tree Fact
Sheets.” University of Florida, IAFS, Environmental
Horticulture. http://hort.ufl.edu/trees/
16
Missouri Botanical Garden. “PlantFinder.” Kemper Center for
Home Gardening.
http://www.mobot.org/gardeninghelp/plantfinder/serviceplantfin
der.shtml
17
Mainland, Charles M. and William O. Cline. “Growing
Blueberries in the Home Garden.” Department of Horticultural
Science, North Carolina Cooperative Extension Service, North
Carolina State University. HIL-8207. Nov. 2002.
http://www.ces.ncsu.edu/depts/hort/hil/hil-8207.html
18
Plant Guide; “Big Sagebrush (Artemisia tridentata).” USDA
Natural Resource Conservation Service, Idaho State Office. 11
pp.
19
Kennedy, Harvey E., Jr. “Silvics of Forest Trees of the United
States.” USDA Forest Service, Agriculture Handbook No. 271.
http://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/fra
xinus/pennsylvanica.htm
20
Whitlinger, Dave. Dave’s Garden; Plant Files.
http://davesgarden.com/pf/
21
Climate and Weather: Data, Information, and Products
Clearinghouse, High Plains Regional Climate Center,
University of Nebraska, Lincoln, NE.
http://www.hprcc.unl.edu/clearinghouse/glossary.html
22
Wozniak, Carl. “Clouds”; Glossary.
www.carlwozniak.com/clouds/glossary.html
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