Growing cactus outdoors in Canada? Really?

Since cactus are normally associated with hot deserts, it comes as a surprise to most gardeners that there are actually four species of cactus that are native to Canada.
Some of these grow almost as far north as the Northwest Territories! Combined with other species that grow at high mountain altitudes in Colorado and throughout the Americas, cacti provide a wide palette of choices for growing in cold climates.
Some of these grow almost as far north as the Northwest Territories! Combined with other species that grow at high mountain altitudes in Colorado and throughout the Americas, cacti provide a wide palette of choices for growing in cold climates.