Sitting here thinking about it, if it were me, Pam, I'd space my live oaks and mag grands about ?20' apart, and to give some quick screening, I'd plant quite a few wax myrtles/myrica cerifera between them. I know 20' is closer together than the books tell you to plant them, but in real life, trees do grow close together, and in the future, the most vigorous mag grands and q. virginianas will overtake the others. Your efforts won't be wasted. The birds will love the wax myrtles, and you'll love the dense, evergreen leaves. Wax myrtles get pretty tall here, so if they get tall in VA, that should help too. And they grow REAL fast - I have to prune mine in the front yard to keep them from taking over other plants.
Instead of using all mag grands, you could use some sweetbay magnolias/m. virginiana - they grow fast, too, especially in wet spots. Live oaks grow fairly fast when they're young, but if you're looking for screening, it'll still take years for them to do that. Mag grands grow real fast down here when they're young, but I don't get the impression from other people's posts that they grow fast in other areas. Of course, my mag grands are all just the ones that come up naturally, no named cultivars.
Another good fast-growing screening plant is yaupon, and it's another good one for the birds.
Sherry

Sherry:

Thank you for the wise advice. You are so knowledgeable (and it's interesting that so many of the same plants thrive in southeastern Va and Mississippi). I'll take your advice.

Southern wax myrtle grows fast here. I prune the wax myrtle trees that grow on the beach - they have interesting forms and pruning allows you to see this. In general, magnolias grow fast here too. I planted a couple of sweetbay magnolias last year during the drought. They had a tough time but are doing great now, have grown taller and filled out. I have no experience with live oaks but hear they are slow. Thanks for the advice about ways to work around them.

Two years ago, I planted a weeping yaupon holly near the house. That holly got off to a bad start when a tropical storm rolled through four months later, uprooted it, and left it 100 feet away. I watered it with fresh water and replanted it, and continued to water it until winter. Now, two years later, it has doubled in size. I'm a big fan of yaupon hollies!

I have a lot of work to do. Most could and should be done in the fall. Although fall planting is best for most plants (I think mag grands are an exception), it's hard to find good stock in the fall. So we run around like crazy people in the spring, trying to get everything planted before the summer heat hits. Then we have to water like crazy to keep things alive. It's crazy!

Fall is so much better. I just wish I could find good stock in the fall.

BTW: All the trees I planted this spring (except the baby seedlings) had a good helping of Black Hen chicken manure.

Thank you!