Need a flowing shrub that grows to 12' or taller and is hardy in zone 5b

Question

We have a day care behind our house, and they built a play gym right behind our 6' fence. When the kids are standing on the platform, their feet are right at the level of the top of the fence. We can't do anything in the backyard without a barrage of questions and comments from our audience. We have a wonderful view of the south end of metro Denver from our back yard in the winter when the leaves are gone and hate to lose that, but during the summer we'd really like to block out the audience.

Answer 1

Plant forsythia grows tall, beautiful yellow flowers in the spring...........then green leaves..............then in the cold weather the leaves drop off until spring starts again. It will create a green tall barrier and some privacy.

Answer 2

I read your message again and that does not sound safe that children are that high up with the possibility of falling over the fence.   I hope this gets resolved peacefully and that no children become injured.