Yes, cacti in Alberta!
Have you wondered about our cactus logo, showing snow on the poor thing? Is this possible? Admittedly it does get a touch cold in Alberta’s winters, but cacti are resilient.
There are two quite common native species, Opuntia fragilis and Opuntia polyacantha. Two other Canadian species are Escobaria viviparia and Opuntia humifusa—not Albertans but cold-hardy too. Escobaria viviparia is also found in Alberta, especially around Dinosaur Provincial Park and south to Medicine Hat. Both O. fragilis and O. polyacantha grow in grasslands, hillsides and ravines almost throughout the province.
O. fragilis, in spite of its name, is not so fragile: it occurs at least as far north as the Peace River valley, hundreds of kilometres north of Edmonton and is the northernmost native cactus in Canada. These cacti are surprisingly cold-hardy: an article by H. Cola-Sanchez in Haseltonia (9: 17-25, 2002), quoting authors Nobel & Bobich 2002, reported these tolerable low temperatures for the four cacti: O. fragilis, -48C, O. humifusa, -250C, O. polyacantha -180C, and O. vivipara, -220C. Wow, what’s a little snow?
Our society has an expert in growing cacti outdoors: Jean W. grows many cactus species out in Edmonton’s winters, and has written about her experiences in the Cactus & Succulent Journal.
Outdoor cacti in Alberta
Cacti that are hardy in Alberta climate love when it’s sunny and dry—just like any other cactus in the world. Find a spot in your garden that gets the most sun and where no plant can survive because it gets so hot. Alberta cacti will benefit from that heat and sun and will reward you with gorgeous blooms in the summer.
Regular garden soil mixed with sand (60:40). To grow, cacti need regular soil as that is where they get all their nutrients and minerals. If planted in sand only, your cacti will eventually vanish. Make sure your soil drains very well. We suggest you raise your flower bed above ground to allow water to escape as quickly as possible. A good drainage system will be especially beneficial during rainy summers.
When it comes to watering, the best thing you can do for your outdoor cacti is to forget that they exist—especially when it comes to new plants. If your cacti flowerbed is out in the open, your prickly plants will get all the water they need from natural rains. However, if it’s been extremely hot for several weeks and your garden did not get a drop of rain, water your cacti. Same is true if your outdoor cacti is sheltered in any way (right next to a house with roof awning, for example)—give them occasional watering to compensate for the rain.
Hardy cacti do not need special care in preparation for or during winter months. You should be aware though that if it’s below 30 and there is no snow, your prickly jewels might get frostbitten. To avoid that cover your cacti with burlap. Fortunately for cacti enthusiasts, Albertans never get snowless winters, so when you shovel your sidewalks you may want to add a couple of shovels of snow onto your cacti flowerbed—just for extra protection.
Cacti that are hardy in Alberta survive our winters because they let themselves dry out in the cold weather. When the spring comes, you’ll find that your prickly plants are rather sad looking—just let them be and with first warm weather, they will get back in shape.
Where to buy winter-hardy Alberta cacti
Certain greenhouses across Canada propagate cacti that are hardy in Alberta (zone 3). Ask around and always make sure that you buy an outdoor variety. Some members of our society are vigilant growers and propagators of outdoor cacti varieties. They will be more than happy to sell you some of their plants. Please feel free to contact us for advice or if you would like to purchase some of our outdoor cacti.
When you are about to buy hardy cacti, make sure they are healthy and do not have insect damage. Steps outlined in the How to Grow Cacti Indoors section are also true for outdoor varieties.