Actually the hardiest cultivars of Southern Magnolia are hardy to temps between -20°F(-29°C) and -25°F(-31.7°C). But that's for relatively short periods of time (hours, not days). Protection from winter sun and wind are both important in preventing leaf burning. I think winter sun protection is a little more important with this though. Even though a tree might have lots of leaf burning, it often will not have any stem or wood damage. The ideal spot to plant one in a border line area would be against a NW facing wall, which would give plenty of heat during the summer (plus retain some heat longer into the night during winter) and also afford some winter sun protection since the sun sets in the SW during the winter(in the Northern hemisphere). Some people in zone 5 that try to grow Southern Magnolias many times report they act more like deciduous trees in having most all of their leaves burned off during the winter, but releaf out in the spring and bloom, so no wood damage is done. I grow more than 1 dozen cultivars of Southern Magnolia here in zone 6 KS and none have been killed or had much of a problem with winter hardiness. Even the supposedly less winter hardy cultivar 'Little Gem' grows fine for me. I also know of many decent sized trees(30'-50'(9-15m) tall range) in the Kansas City metro area which have been through their all time record low temp of -22°F(-30°C) and the very tough, cold winters of the late 1970's and early 1980's. So, I think in general most Southern Magnolias are zone 6 hardy and a few can make it in protected spots in zone 5. Duration of cold is important as is summer heat. If you live in a colder area with abundant summer heat(temps mostly in the 80's(26°-31°C) or warmer for most of summer), you probably have a better chance at growing Southern Magnolia than an area with little or no summer heat and relatively mild winters.

Up here I bet the both would grow there. In the woods there are plenty of Redbuds and Dogwoods growing within five feet of huge trees so I know they'll survive. For my yard I'd try to go at least 10 feet apart minimum just for personal preference. Eventually their crowns will touch and I feel the mix of white and pink flowers from dogwoods and redbuds will be attractive if they bloom at the same time. I had a white ash and dogwood about 15 feet apart. Really the shade of the big ash didn't affect the shape of the dogwood hardly at all. I had a silver maple and redbud maybe 20 feet apart, the redbud still has a lean away from where the maple was and didn't grow much in its shade.

well....janlep....I'm out in Palm Springs so conditions are probably different from where you are. I can't plant anything against a west wall as the radiant heat cooks anything I plant there....BUT.....if you are closer to the ocean then you should be fine with that part of it.... Now...back to the house/foundation issue. I've got a 9 year old Manila Mango planted maybe...let's see about 6 feet from the house and there's been no problem and I don't foresee one for your's either. A Mango sends down a deep tap root so it should not bother the foundation at all. Also, it eventually cleared the house and the canopy is now free to rise and spread. You'll see in the photo I have a 4 foot overhang on my roof too.... Good luck and happy eating. If it's a 4-5 foot tree that you bought at Lowe's or Home Depot you'll have to wait till about the 4th year or so to get your first fruit...but it will be well worth the wait....Fertilize with a diluted amount more often than a stronger dose less often. I fertilize every couple weeks with something like 1/3 the dose they say on the instructions.... Good luck - mangodog

You can certainly containerize them in the short term for a few years. But I am not sure of your goals. Are you planning on keeping some containerized and planting the rest..., in your area (Chicago)? You are liable to hear multiple accounts regarding growth RATE as it would vary depending on...., soil conditions, CLIMATE (temps and rainfall), etc. I have not grown mine from seed but from small trees...., in NJ,...in Zone 7, in the GROUND, etc. If you are growing them in containers in less than optimal conditions, they are not going to grow as fast. I planted several of mine in 2009 from trees that were around two feet tall. The pics below are from a few years ago..., they are now up to the attic level of the house. I would not say that is SLOW!