Evergreen screen for shade and clay soil
I'd like to plant an everygreen screen to block out the view of the neighbor's dog run. The area is 100 feet long and there are 4 large mature maple trees shading it already. I'm in Southern Indiana, so I've got heavy clay soil. This site is at the top of a small rise (3 feet, apx.) so it should be well-drained, as that goes around here!
Of course, I want this to grow as fast as possible, as in yesterday. :-) I'd like to go for a more natural, woodsy look, rather than a straight line of arborviate or a trimmed hedge. One last requirement -- I'd rather the trees not get too huge, since there are power lines right over the property line. (So white pines are out) Oh, and I have a toddler, so nothing poisonous -- Yews are out too.
What would you recommend?