Is it possible to grow a magnolia grandiflora (southern evergreen) in Toronto?
Thank you for your question. Judging from the large number of magnolias I see blooming in the spring, many home gardeners love magnolias!
Toronto’s plant hardiness zone is Zone 6 (with Zone 6b being the region closest to Lake Ontario, and Zone 6a being further from the lake). If you live in the north end of the GTA (such as in Richmond Hill, for example) or your garden is in an exposed location, your zone could be 5A or 5B. Plant hardiness zones are important to be aware of when purchasing plants, especially if we are considering a species we might love but is typically grown further south in the USA. If you live in Zone 6, then it is highly likely that plants rated at Zone 6 or lower are a good choice for your garden.
(Please note that plant hardiness zones are different in the USA. If you are looking at websites that are American, Toronto is in Zone 5 using the USDA Hardiness Zones. For more information about plant hardiness zones please see this article.)
This article from Magnolia Society International describes the hardiness of Magnolia grandiflora as USDA Zones 7-9 (which puts it two zones away from what we experience here in Toronto, knowing that Toronto is in Zone 5 using the American scale).
However, there are a number of magnolias which will grow in Toronto, including a native species, the cucumber tree (Magnolia acuminata)! This article from the Toronto Master Gardener’s website describes Star Magnolia, Magnolia stellata, as a species particularly well suited to Toronto. Likewise, some cultivars of Saucer Magnolias, Magnolia soulageana, will also grow well here.
So the bad news is that Magnolia grandiflora is not suited for our cold winters and shorter growing season. The good news is that there are many beautiful magnolias that will thrive here, providing you with a good selection to choose from.