Canadian Hemlock used for hedges
I was hoping someone could help me answer some of my questions regarding planting Canadian Hemlocks as a hedge along the end of my backyard... I have a wooden fence at the back of my yard (right side in my photo) and I would like to plant Canadian Hemlocks along the fence acting as a hedge for privacy puposes. However, I also have a Manitoba Maple (left side of my photo) that is fully matured, so I'm worried about planting the Canadian Hemlocks too close to the maple. To make matters worse, there is a cedar hedge on the other side of my fence that has thined out quite badly, likely due to the shade. I'm chosing to plant the hemlocks because I've read that they work well when planted as hedges and grow well in shaded areas. As you can see from my photo, I'm removing these massive concrete blocks from my yard that line my fence so I felt it was a good opportunity to re-soil and plant an evergreen hedge. I want to plant the hemlocks in a row about 45 feet long and I want to prune them so they don't grow too wide, but instead tall. My questions are:
1. How far apart should I plant Canadian Hemlocks from each other if I want a thick hedge?
2. How far apart should I plant Canadian Hemlocks from the fence? and how far apart from the Manitoba Maple?
3. Should I create a barrier in the soil between the hemlocks and the maple or the fence to restrict the hemlocks to the fresh soil? If so, how deep?
Thanks for any help you can offer. I am a new homeowner and fairly new to landscaping/tree planting/gardening...