I just got a question about the Swedish Columnar Aspen. It is used very often as a quick-growing privacy screen. The leaves make a nice rustling sound in the breeze. It's a really nice tree, but it is so overused. And not only is it a short-lived tree (generally, short-lived qualifies as about 20-30 years), but if there is ever some kind of disease that hits aspens, then it is going to spread like wildfire around Calgary. I think it's time for people to diversify.
Still, lots of people have tiny backyards so a columnar tree is needed. Fortunately, nurseries are introducing new varieties almost every year. There is a columnar caragana, is very hardy and drought-tolerant for our prairie conditions.
But my favourite are the columnar crabapple trees, especially Gladiator. This tree has beautiful purple foliage (dare to be different!), pink flowers in spring, and no fruit to pick up in the fall. It is prairie hardy and grow to about 20 ft tall. I'm thinking of getting one myself...
Does anyone else have some suggestions?