When it comes to gardening trends, there is one that shows no signs of diminishing: shrinking yards. Smaller yards will, quite literally, narrow your choice of trees that perform well in these small landscapes. So, if you want to grow a tree or two, choosing varieties that are destined to become tall, sprawling giants is not a good idea.
But the good news is that bigger doesn’t mean better when it comes to trees, and some of the very best varieties have a small stature without sacrificing any beauty.
A Bit of Science
Why are some trees much smaller compared to their larger cousins? Harsh environments are one reason. Hike to the higher elevations in Jasper or Banff and you’ll see dwarf evergreens that are a fraction of the size of the same species growing at lower altitudes thanks to the short growing season, poor soil and cool temperatures.
But there are also many varieties of normally large tree species that are naturally dwarf and will not grow too tall or too wide even in optimum growing environments. The reason these plants are dwarf is primarily due to a deficiency of specific plant hormones. One particular group of plant hormones called gibberellins are responsible for elongation of shoots and branches in most plants, but some trees are deficient in gibberellins because of genetic mutations so they remain relatively small compared to their larger cousins.
Plant breeders are constantly on the lookout for dwarf trees to select and use in their breeding programs. And given the increasing number of ‘postage stamp’ yards that we see today, there is an increasing demand for beautiful but smaller trees and shrubs.
What should you do?
Keep in mind that dwarf woody trees still grow! Even though they are classified as dwarf, they still require space to reach their full potential. Therefore, it’s important you always choose dwarf tree and shrub varieties that fit nicely into your yard and that won’t outgrow their allotted space at maturity. Check the labels for information about mature heights of whatever varieties you choose.
Also ensure that the dwarf plants are hardy. For example, I commonly see a dwarf spruce called ‘Dwarf Alberta Spruce’ being planted in our region. It’s a beautiful spruce but ironically is not all that hardy in Alberta. It suffers tremendously from winter drying and needle drop and typically struggles for a few years before dying outright.
If want to plant some dwarfs, here is shortlist of some great performers for our region.
Dakota Pinnacle Birch
- A columnar birch that is tough and grows quickly and provides a nice privacy screen. It tends to cling-on to its leaves over winter adding some additional privacy outside of the growing season
Purple Spire Flowering Crabapple
- Grows to about 5 metres tall and just over a metre wide. Purple leaves and pink flowers really enhance this crabapple’s ornamental value.
Regal Prince Oak
- This columnar oak grows about 8 metres tall but is only about 2.5 metres wide. It produces leaves that are rich-green on top and silver on the bottom.
Pyramidal Mountain Ash
- Slow growing tree with dark green foliage in the summer turning to a beautiful yellow-red in the fall. Its fruit is attractive to birds which is great if you are a bird lover!
Finally, never transplant a ‘cute’ tree in your yard without understanding its true personality. An innocent-looking white, spruce seedling will eventually grow into a 20-metre tall, wide-spreading, giant. There will be a dwarfing effect, but it will be due to the illusion that your yard is gradually shrinking as the spruce continues to grow!
