Answer: Most of the traditional evergreen southern magnolias (Magnolia grandiflora) are considered winter hardy into zone 7. Your zip code places you in zone 7A, the coldest part of zone 7 -- as you know.
For this reason I would suggest you limit your selection to only the hardiest cultivars such as Bracken's Brown Beauty or Edith Bogue, for example. This first is a large tree, 30 to 50 feet tall and 15 to 30 feet across. This is an evergreen and will tolerate partial shade so would be well suited for your site in all morning sun. As with any of the evergreen magnolias, it needs protection from winter wind. It also needs an organic, acidic, evenly moist yet well drained soil, as do all the southern magnolias.
Edith Bogue is another hardy evergreen cultivar but a bit smaller, growing to about 30 feet tall and 15 feet wide. If your sun lasts all morning and includes the noon hour, then it will be sunny enough for this one as well.
If you are looking for the overall impression of a southern magnolia, you will probably not be happy with the M. virginiana (the native sweetbay). This is likely to be deciduous for you.
Here is information about the "southern sweetbay" or M. virginiana var australis which I would expect to be semi-evergreen -- at best -- for you. You may need to cut and paste the complete url into your browser to make it work correctly.
You may also want to discuss this with your local professionally trained nurseryman and possibly your local county extension to see if you have a site that is well suited to a magnolia and what to expect. If not, they should be able to suggest substitutes. Best of luck with your new tree.
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