Trees and shrubs for southern Alberta

Southern Alberta is known for endless prairie landscapes with natural cottonwood and some willows. Closer to the mountains and foothills there are plenty of white spruce, pines, aspen, balsam poplar and in some places Douglas fir. Most of the trees you see around yards, fields, streets, parks, and RV campgrounds were planted in the last 120 years. Some natural regenerated bluffs of aspen, spruce and pine occur in areas that are sheltered or protected in the coulees or north slope exposures.

Southern Alberta’s climate presents unique challenges for gardeners and landscapers, particularly due to its arid conditions and limited water availability. However, with careful planning and the selection of drought-tolerant plants, it’s possible to create beautiful and sustainable landscapes that thrive even in times of water scarcity. The following are key factors to consider:

Soil

There are many types of soils in southern Alberta from very rich to very poor. Each soil type can be a friend or foe to trees. There are four major types of soils:

• Clay soil – is very hard for trees to grow in clay as dense soil particles do not allow roots to go through and do not provide enough access to oxygen or moisture for roots. Trees that are adaptable to heavy clay soil are cottonwoods, some hybrid poplars, and some ash species
• Sandy soil – is very porous, not nutrient rich, and does not hold water at all. Some trees such as pines and juniper love sandy soils and even thrive.
• Saline soils – are very hard on any tree and shrub species, but there are some shrubs such as silver buffaloberry that can handle a level of salinities.
• Compacted soil – many town or urban areas have a huge problem with soil compaction due to roads or house building requirements. Compaction is even worse for trees than heavy clay soil as there are no pores for air or water pockets and roots simply can’t go through. The depth of compacted soil is very important – if soil is just compacted on the surface some tilling and other soil amendments can be used to break down the compaction. If soils are very deeply compacted and there are some 4-6 inches of topsoil you may plant shrubs and some tree species that can live on topsoil that was put over compacted area.

Wind

Relentless wind is characteristic in the prairies. The prairies are notorious for relentless winds that desiccate the landscape and takes all moisture from the air. Selecting wind-resistant tree species is imperative but not easy task as certain trees exhibit better resilience to wind forces than others, contributing to landscape stability and longevity.

Elevation

Elevation in southern Alberta ranges from just below 700 meters near the Saskatchewan border to 1100 meters in parts of Calgary and rising up further west. This elevation difference impacts how some trees grow, as higher elevations are colder and could limit the growth of many trees, especially hardwood species. Check out this web site for elevation near you https://en-ca.topographic-map.com/maps/qus/Alberta/

Water

Water is scarce in the prairies and many trees may not develop deep roots to access water that is further from surface. Test your water prior to watering your trees. If it contains high levels of sodium, it will kill your trees fast and not provide chances for them to survive. Some trees can handle drought better than others-e.g. pine are more drought tolerant than poplars, elm, and many others.

Establishment  

For the prairie region one of the most common mistakes is planting trees in open areas with no protection from wind and heat, no site preparation and with little watering. Once you know your soil you must do tilling or some soil preparation prior to planting trees. The next thing which is extremely important is that you may need to plant some shrub species and let them grow for 2-4 years prior you plant any tree species. These shrub rows will protect young trees from the relentless wind that takes the moisture from the air and will keep moisture/snow on ground and around roots of newly planted trees longer.  Using plastic or any other type of mulch is also a must in southern Alberta.

Care and maintenance

Watering  and looking out for insects, weeds and diseases is crucial once you plant trees. Without proper weed control chances of their survival is very limited. Water when you must and do not over water as it will weaken your trees in the long run. For your local conditions there are several things to consider as there are big differences between the areas around Hanna and around Airdrie or Pincher Creek:

• Visit already established shelterbelts, windbreaks, parks, or neighbours to see what trees/shrubs grow there, how they are established and what the good, bad or ugly things about them are.
• Local exposure – northern slopes are colder with more moisture; southern slopes get more light but are drier
• Differences in prevailing winds and local infrastructure
• Amount of snow accumulation during winter and rain during growing season is vastly different – choose trees/shrubs that fit your local moisture availability 

It is crucial to understand site conditions prior to choosing any species to plant. Growing conditions inside a city are entirely different than just 10 miles away from a city setting.  The same principle applies to small towns and farms. Local site conditions are so variable that you have to pay attention in detail to fully understand what grows best on your property.

The following table is based research papers and publications done by various organizations and institutions as well as through my personal communication with city, town and county staff and visits to many farms, city, towns and hamlets. It does not cover every aspect of tree characteristics but is a starting point for you to consider when planting trees or shrubs on your property.

Table 1. Tree species for Southern Alberta
Tree species	Latin name	Hardiness Zone	Moisture	Site tolerance
Fat Albert Spruce	Picea pungens ‘Fat Albert’	2b	Dry	Salt/Drought
Colorado spruce	Picea pungens	2b	Dry	Salt/Drought
Colorado Blue spruce	Picea pungens “Glauca”	2b	Dry	Drought
White spruce	Picea glauca	2b	Adaptable	Adaptable
Black hill spruce	Picea glauca var. densata	2b	Dry	Salt/Drought
Lodgepole pine	Pinus contorta var. latifolia	2a	Dry	Drought/Cold
Scotch pine	Pinus sylvestris	2a	Dry	Salt
Ponderosa pine	Pinus ponderosa	3a	Dry	Drought/Wind
Jack pine	Pinus banksiana	1a	Dry	Drought/Wind
Austrian pine	Pinus nigra	4a	Dry	Clay/Salt
Swiss Stone pine	Pinus cembra	3a	Wet	Adaptable
Mugo pine	Pinus mugo	2b	Dry	Drought
Limber pine	Pinus flexilis	3a	Dry	Drought/Wind
Siberian Larch	Larix sibirica	2b	Dry	High Acidic soil
Douglas Fir	Pseudotsuga menziesii	4a	Adaptable	Rocky soils/fire
Subalpine Fir	Abies lasiocarpa	2a	Dry	High elevation
Rocky Mountain Juniper	Juniperus scopulorum	3a	Dry	High pH/salt
Brendon Cedar	Thuja occidentalis ‘Brandon’	2b	Dry	Cold
American Elm	Ulmus americana	2a	Wet	Clay
Brandon elm	Ulmus americana Brandon	2b	Wet	Clay
Siberian Elm	Ulmus pumila	2b	Wet	Drought
Bur Oak	Quercus macrocarpa	2b	Adaptable	Drought
Northern Pin Oak	Quercus ellipsoidalis	3b	Dry	Drought
Ohio buckeye	Aesculus glabra	2b	Adaptable	Wet
Honey locust	Gleditsia triacanthos	3a	Alkaline	Drought/Salt
Hackaberry	Celtis occidentalis	3a	Adaptable	medium drought
American Linden	Tilia americana	2b	Moderate	Wet/flooding
Dropmore Linden	Tilia x flavescens ‘Dropmore’	3a	Moderate	Adaptable
True North linden	Tilia americana ‘Duros’	2a	Moderate	Wet/flooding
Littleleaf Linden	Tilia cordata	3a	Moderate	Wet/flooding
Amur maple	Acer ginnala	2a	Moderate	Drought
Silver maple	Acer saccharinum	3b	Moderate	Salt
Manitoba maple	Acer negundo	2a	Adaptable	Salt/Droughts
Hot Wings Tatarian maple	Acer tataricum ‘GarAnn’	3a	Alkaline	Drought
Sensation Box Elder	Acer negundo ‘ Sensation”	3a	adaptable	Drought
Paper Birch	Betula papyrifera	2a	Moderate	Shade
Green Ash	Fraxinus pennsylvanica	2a	Wet	Salt/Wet
Foothills Green Ash	Fraxinus pennsylvanica ‘Foothills’	2b	Dry	Drought
Black Ash	Fraxinus nigra	2a	Wet	Wet/flooding
Patmore Green Ash	Fraxinus pennsylvanica ‘Patmore’	2a	Adaptable	Drought
European Mountain Ash	Sorbus aucuparia	3a	Adaptable	Adaptable
Acute Leaf Willow	Salix acutifolia	2b	Wet	Flooding/clay
Golden Willow	Salix alba “Vitellina”	2a	Wet	Flooding/clay
Laurel Leaf Willow	Salix pentandra	2a	Wet	Flooding
Byland Green Poplar	Populus x ‘Byland Green’	3a	Moderate	Drought
Tristis Poplar	Populus x ‘Tristis’	3a	Moderate	Drought
Prairies Sky Poplar	Populus x canadensis Prairie Sky	2a	Moderate	Drought
Eastern Cottonwood	Populus deltoides	2a	Poor soil	very adaptable
Plains Cottonwood	Populus sargentii	2a	adaptable	Drought
Poplar Northwest	Populus x ‘ Northwest”	2a	adaptable	Drought
Brooks Poplar	Populus x ‘ Brooks”	2a	wet	flooding/clay
Balsam poplar	Populus balsamifera	2a	wet	flooding/clay
Paskapoo Balsam Poplar	Populus balsamifera ‘Paskapoo’	2a	adaptable	very adaptable
Flowering/fruit trees
Japanese tree lilac	Syringa reticulata	3a
Starlight Flowering Crab	Malus x ‘Jeflite’	2a
Thunderchild Flowering Crab	Malus x ‘Thunderchled’	2b
Amur cherry	Prunus maackii	2a
Ivory Silk Tree Lilac	Syringa reticulata ‘ Ivory Silk’	3a
Evans Cherry	Prunus ‘ Evans’	2b
Pembina plum	Prunus ‘Pembina’	2b
Varieties of other cherries	Prunus sp	3a
Usurian pear	Pyrus ussuriensis	3a
Hawthorns	Crategus spp	2a
Varieties of Crab apples	Malus spp	2b
Chockcherries	Prunus sp	2a
Shrubs
Caragana	Caragana arborescens
Silver buffaloberry	Shepherdia argentea
Saskatoon’s	Amelanchier alnifolia
Lilac	Syringa villosa
Potentilla	Potentilla fruticosa
Chockecherry	Prunus virginiana
Nanking cherry	Prunus tomentosa
Cotoneaster	Cotoneaster integerrimus
Seabuckthorn	Hippophae rhamnoides
Silverberry	Elaeagnus commutata
Roses	Rosa species
Forsythia	Forsythia x‘Meadowlark’