Calgary is a tough place to be a tree, always has been. There are four native trees here—only four types of trees grew here when our forefathers arrived. Many introduced species have now naturalized, but at core those stalwart four remain.
They Are:
- The Trembling aspen
- The Balsam Poplar
- The White Spruce
- The Rocky Mountain Douglas Fir
The trembling aspen is the only native tree brave enough to leave the river valley. The aspens' chosen location is the hillsides of our rolling prairie landscape.
Of the other three native trees, the Balsam Poplar thrived in the riparian community of the Bow River bottom.
The White Spruce and the Rocky Mountain Douglas Fir grew in the sheltered, snow holding steep south sides of the river valley.
That's it! Four native trees, everything else here is either shrub material or introduced.
Why so tough? And why are there so few? Calgary exists in a uniquely tree unfriendly weather area, exposed on the prairie to the full Arctic brunt, yet close enough to be strongly influenced by mountain weather.
It is the chinook, our joyous and strange winter miracle.
With its strong drying winds that can go on for days, that so reduces Calgary's natural tree population. The chinook can fool trees into thinking spring has arrived and at the same time dry trees out to the point of death.
It is these unpredictable and changing conditions that kept the native numbers so low.
Calgary sits on the cusp of two hardiness zones, 2 and 3. Those are pretty severe numbers. Hardiness zones are a system that was developed so that gardeners and horticulturalists could know what introduced plants would survive. Basically the arctic pole is a zero and the tip of Florida is a ten.
These zones have no straight lines but squiggle around mountain ranges and cold flat prairie areas.
A North American hardiness zone map looks like a sort of paint-by-number outline Tthere is a lot of variation as you move around, but the system works.
Most of Vancouver Island is either zone 6 or 7. IF you bring native plants from there to Calgary, they will be dead before Christmas. If you want a tree to have a fair chance of survival you need to stay with plants that have a zone 3 rating; any higher, a cold winter or weird weather combination will come and that tree will probably die.
Planting trees is not easy; it looks easy and all of us have killed a few young trees, to prove that it is not easy. Without a short lesson in tree anatomy, most of us get it wrong. I have written extensively about the art and science of planting on my blog in my website.
Here are seven posts dealing with everything from initial selection through to planting and staking as required:
- Planting 1: Species selection
- Planting 2: Site selection
- Planting 3: Buying your tree
- Planting 4: Root crown identification
- Planting 5, Digging the hole, planting the tree
- Planting 6: Staking
- Planting 7: Watering
Below is a list, two lists really, of Calgary's proven tree species, one for evergreens and one for broadleaf trees, those that lose their leaves in autumn.
About Calgary Evergreen Trees
Evergreen, what a great name, trees that are forever green. Evergreens are conifers, they retain their leaves, needles through periods of years. Cone bearing plants. their flowers, such as they are are on separate parts of the tree. The male flowers produce pollen, the female flowers at first are beautiful miniature cones, many times a purple color. And later are the mature cones with the seeds tucked down inside , tightly between the scales of the mature cone.
Evergreens are ancient plants as old as 300 million years. They are simple in design, very tough and prefer more northern, cooler climates. The great taiga, a biome circling the planet below the north polar region, is mostly evergreens.
In Calgary we are blessed with a good count of evergreens that thrive here. One ironic note is the fact of the lodgepole pine, native as close as Bragg Creek. It is the pine that fails more often than any of the introduced species.
In the forest they always grow together in great communities, and the needles, dead trees and all other parts of natural forest floor duff seem to keep them strong. A single planting in a Calgary lawn is the opposite of that.
List of Best Calgary Evergreen Trees:
- Mugo pine,
- Scots pine,
- Bristlecone pine,
- Swiss stone pine,
- Eastern white pine,
- Ponderosa pine,
- Austrian pine,
- White spruce,
- Colorado blue spruce,
- Norway spruce,
- Colorado silver Fir,
- Balsam Fir,
- Sub-Alpine Fir,
- Douglas Fir,
- Tamarack,
- Siberian Larch.
This list is not exhaustive, I could list many, many more. I have focused on the best, the hardiest trees, the trees with the least problems. There are many smaller and dwarf cultivars that are available and these small evergreens can add amazing interest to a garden, but that, my friends, is another post.
Calgary Pine Trees
Mugo pine, a Swiss import, very hardy, there are several different types. Some grow fast, some slow. If you want a slow growing compact form and you buy a fast grower you will not be happy. Needles in groups of 2. From 2 feet to 50 foot trees.
Scots pine, a prairie standard very hardy, and drought tolerant. Beautiful exfoliating orange bark. Needles in groups of 2. Can grow to a 50 foot tree.
Bristlecone pine, an import from the dry American S.W., slow growing, thick needle growth. Needles in groups of 5, a 25-footer is a big one.
Swiss stone pine, another Swiss import, beautiful tight smaller narrow tree. 25 feet of height is a big one. Needles in groups of 5. Bright pewter bark.
Eastern white pine, amazingly this eastern forest giant does quite well here. Logged extensively in the east, these were the great masts of the Royal Navy. Smooth grey bark, needles in groups of 5. Graceful.
Ponderosa pine, a giant from the B.C. interior, fully hardy here. I have never seen one taller than 30 feet. In maturity large orange corky plates of bark, lovely. Long needles in groups of 3.
Austrian pine, another European, maybe the best pine for Calgary. A full wide crown, beautiful silver/pewter cork bark. A large one would get to 40 feet. Needles in groups of 2.
Calgary Spruce Trees
The next major group of evergreens is the spruce. Tall pyramidal, tough and long lived. Spruce trees can live in the right conditions for hundreds of years. Spruce logged in hidden creek in southern Alberta were 500 years old. The oldest planted, still extant spruce are in our oldest neighborhoods. Mount Royal is a good start if you are hunting for giants. The oldest are at least 100 years old and some are close to 100 feet high.
These are not only words of awe and praise, they are also a warning. All non-dwarf spruce attain great size , even in 50 years. Many a house with a row planted along the south side, soon became a house fully in the shade. To lose all your winter sun to an enthusiastic overplanting is not a good idea.
That said, a single spruce well placed can be a joy to see year round.
White spruce, the native tree, all spruce have single needles, they are never in groups, like the pines. As said above, these get big; if you have a good open location, then go ahead, they are tough, drought tolerant to some degree, if watered occasionally, relatively pest free. They do have their problems and a weak tree infested with yellow headed saw fly is in trouble.
Colorado blue spruce, an import, thrives and is naturalized here. Available in a spectrum of colors from a flat green into the blues and even silvery blue. Inch-long stiff sharp needles and 3-4 inch long golden cones help identify the Colorado. Size and growth pattern similar to the white spruce, usually a wider tree than the white. Very aggressive in the landscape, crowding space and light and hogging water resources. Choose your planting site very carefully.
Norway spruce, another import, is under utilized and is a graceful beauty. Size and all other planting concerns mentioned above still apply. It is the shape of the Norway that is so attractive, the branches swoop up, they leave the trunk and arch upwards creating a pleasing appearance. The Norway produces large unmistakable cones that can be 7-8 inches long with a 2 inch diameter.
Calgary Fir Trees
The next group of evergreens are the firs. Firs are mountain and coastal trees, so here in Calgary the numbers are low. Of the true firs only the Colorado silver fir has made a stand. In native Colorado they attain great height as most mature evergreens do; here I have never seen one taller than 45 feet. Bright silver bark with sap bubbles in the younger bark and nearly 2 inch long silver/blue needles give this tree a handsome look. This tree is severely under utilized in Calgary.
A fir very rarely planted here is the Sub-Alpine fir from close by in our mountains. Another is the Balsam fir, a northern forest tree.
The Douglas fir is a single species with no related tree family here. These are not true firs; scientists call them false firs. That said, the two varieties here in western Canada are magnificent trees. The coastal giant is well known (have you visited Cathedral Grove?); most of those preserved giants are Douglas ir.
Here on the eastern slopes we are blessed with the rocky mountain Douglas fir.
Calgary's Douglas fir trail is a great place to meet your elders. Many of the largest trees are at least 500 years old! Planted in the landscape the rules that apply to spruce trees would work here also. Very tough and trouble free tree.
One feature of the cone can be used for 100% correct identification. Between the cone scales is an additional tissue called a bract. This forked snake's tongue shaped brown tissue is present only on Douglas fir.
Calgary Larch Trees
Our last group of evergreens is the larch. Larch are amazing and do something no other evergreen does. Each fall they drop their needles, but not before an amazing color change from a warm green to a canary yellow. Ever been to Larch valley? Something to see! The larch of the mountains does not grow here but two of its cousins, one from Europe, thrive here.
The tamarack is native just north of here and as far east as Hudson's bay. A classic conical evergreen form, the tamarack is a strong tree, able to deal with wet conditions, in the native setting is near boggy country. Tough and nearly problem free, it is greatly under used here. Excellent fall color.
The other larch is the ever popular Siberian larch and if you know a larch it is probably this species. This conical shaped evergreen has quite a wide base, when the oldest lower branches are left alone. The branching habit is somewhat like the Norway spruce and they swoop, or lift up towards the branch tips. Very hardy and nearly problem free, the Siberian larch is a great evergreen choice, the big bonus being that they allow winter light through, so can work well as a summer, south side shade tree.
Broadleaf Trees to Follow soon!
Kevin Lee, Arborist, Tree Surgeon, Calgary Arborist, Calgary’s Tree Whisperer
Learn About My Services Here https://krltreeservice.com/services
