Yes, Calgary has a very short "growing season". If you define the season from the last frost in the spring to the first frost in the fall. But perennials last much longer than that and of course, shrubs, trees and evergreens extend the season even further. This late fall has been glorious - the first Hallowe'en the kids didn't have to try to squeeze their costumes over winter coats and mitts! There are many shrubs and perennials still looking very colourful in the garden right now.
Since my two main criteria for choosing plants is that they must be low maintenance and must have a long season of interest, it just so happens that many of the plants still looking good right now happen to be many of my overall favourites: