I would like advice on fast growing trees that I can be used for privacy screen. The area is 50' in length and is on a slope, gets full sun, (sun all day long), hardiness zone is 6. I would like the trees to be cost effective since I am going to need probably a large quantity. I am trying to block out a building at the rear of property so I will need the tree to get pretty tall (20' or taller) pretty quick. I would like a spread of 5-10'. My research has pointed me to hybrid willow and thuja green giant. I would like to know if there is any better ideas for this area. Any advice would be greatly appreciated.

We have an iris bed about 20 feet long and 5 feet wide. At the moment the leaves are five or six inches tall. There has been a major storm here and the ground is saturated. We have just learned that there is a major problem in the wall on that side of the house that will require extensive repair, some demolition, some heavy equipment, etc. Is there a way I can try to lift some of the irises to protect them and then replant when the contractors are finished? If so, how do I care for them in the meantime? If I just leave them and they are trampled, will they come back? Thanks for whatever advice you can give.