https://www.houzz.com/discussions/6428777/bbb-edith-bogue-kay-parris-alta-victoria-what-to-choose-for-z6

https://www.gardenweb.com/discussions/2041600/magnolia-bracken-s-brown-beauty#n=22

Based on the information I've seen (from other sources as well as a number of discussions on Houzz) the general consensus seems to be that Brackens Brown Beauty and Edith Bogue are the hardiest varieties available, with Victoria also quite cold hardy but perhaps slightly less than BBB and EB. There is also a new introduction called 'BooneArb' that per the patent claims to be hardier than BBB and EB, but I don't think it is commercially available (or widely tested) yet.

Photo below of a young Victoria at the Chicago Botanic Garden (Dec 2023)

Amazing if that Victoria survives long term in Chicago. I see no real difference in my zone comparing EB with Victoria, but subtle differences in hardiness may show up in more severe winters. Both offer good snow resistance and that is important. (Have no experience with BB Magnolias.) Nice thing about the Victoria is the reddish floral buds (almost look like F. elastica). Both are very robust cultivars, with branches reaching down to the ground.

Standard southern mag at brother's house some yrs ago (z6 west MD). Certainly went thru Jan 1977 cold wave with -15 F temps and Jan 1994 w/even colder temps. Brother did say that it lost alot of leaves from those temps, but recovered.

What would happen to a southern magnolia if a foot or more of heavy wet snow accumulated on the leaves and branches of this tree? In Ohio we can have early snowstorms that will snap off and take down large branches of deciduous trees that haven't shed their leaves for the winter yet - (maples, crabapples, hawthorn, deciduous magnolias, Bradford pear, etc., ) - honestly I don't feel so bad about the Bradford pears but I have seen the whole top of mature pear trees and hawthorn taken completely out by an early snow storm and the only thing left is the main trunk.

Can the southern magnolia withstand a lot of snow weight on its leaves and branches? Somehow I don't think this tree is well suited for areas that can get several feet of snow during a snow event. I have lived long enough to see a good amount of damage done to trees by the snow.

Southern magnolias might be able to take the cold winter temperatures that we have in Ohio but what about a heavy snow load?

Depends on the cultivar of M. grandiflora. I am on the East coast, Mid Atlantic, we specialize in heavy, wet heart attack snow. Edith Bogue, Victoria, even the Majestic Beauty, all will behave by having their branches bend toward the ground in response to HEAVY snow loads. I have seen this repeatedly throughout the yeas, talking about 1-2 plus FEET of snow. Then, once the sun comes out and temps rise to near freezing, they start bending right back up again. It really is amazing. YES, they may lose an occasional branch, but these cultivars are so vigorous that they soon fill in again. Then, there are cultivars of the same species, curiously the more vertical growers in my experience, that just SNAP, the sprawling, luxuriant, ones with a lot of horizontal growth did not show damage. However, we seldom have ice storms, I am guessing those are worse on trees. Years ago, we had a freak Halloween snow of 4-5 inches while northern trees (including deciduous magnolias) were still in full leaf, we saw trees SLIP in half but no issue for the Southern Magnolias. I guess the branches and wood are rather soft and pliant and bend rather than snap. Another consideration for some growers (say in more maritime/cool summer climates) is that they do not get enough summer heat for the wood to ripen, thus weaker for supporting snow loads. But Jeb, if you are a zone 5, the intensity and duration of cold WILL be a factor more than the snow. M.g. often considered to be a strong "indicator species" of a solid Zone 7 climate (though they do sneak by in somewhat colder zone, like 6b. They are interesting species, fairly shallow-rooted and yet surprisingly, both wind and drought tolerant. Also, never had issues with pests. Even deer repellent, save for the fact that deer love to rut the trunks if they can get near them, so don't "limb up", the other branches will protect the trunk.

P.S., These are Edith Bogue, after branches have already begun to rise. Can almost compare it the amazing transformation in the local bamboo forest, after a heavy snow, all the culms bend toward the ground and in a day or two, are standing vertical again.

@jeb "What would happen to a southern magnolia if a foot or more of heavy wet snow accumulated on the leaves and branches of this tree?"

Jeb, that's pretty much what happened to my Victoria this past Jan from a sopping wet snow. First time ever after near 20 yrs that it experienced alot of branch breakage. Yet, every broken branch broke "clean" and didn't leave a gaping stripped-away wound. And looking at it now, it was/is so dense that I can't even tell anything happened unless I do a close inspection.

They ARE, afterall, robust, STEEL MAGNOLIAS.