A perennial is a herbaceous (non-woody) plant that lives more than two years. The top growth usually dies back to the ground in colder climates.
Not all perennials are hardy in all areas. Each perennial has its own hardiness rating based on temperature. The hardiness zones tells you the lowest temperature the plant can withstand. Our Calgary area is Zone 3 (up to -40C). So look for plants that are listed as Z3 or Z2 (up to -45C).
Although perennials do not need to be planted every year, more time in planning is required. Each perennial has a specific bloom time and if you want to create continuous colour, you will need to choose a variety of plants that flower in Spring, Summer and Early Fall. Other factors to also consider are height and spread of plant, also flower size and texture and light requirements.
Achillea (Yarrow), Aquilegia (Columbine), Armeria, Astilbe, Brunnera, Campanula (Bellflower), Coreopsis, Delphinium, Dianthus, Dicentra (Bleeding Heart), Digitalis (Foxglove), Echinacea, Euphorbia, Gaillardia, Geranium, Hemerocallis (Daylily), Hosta, Iris, Lavender, Liatris, Ligularia, Lupines, Monarda (Bee Balm), Peony, Phlox, Poppy, Rudbeckia (Black Eyed Susan), Salvia