Shrub, Hedge, or Tree

Hello I am a beginner and I am looking for some advice to screen out some of the visibility from my house to a road (basically build a privacy wall). I live sort of in between zones 5 and 6. My issue is this: I have two 40-50 ft Ash trees planted about 8 feet apart. There is a chain linked fence just on the outside of the trees. I want to plant something that will grow up and block out the 6-8 ft range between the two trees but not grow over 20 feet. My concerns are that it is not sunny enough there -- It's probably 50% sun /50% shade. Also will the roots of the trees create a major problem for anything planted/ growing? I am thinking of trying forsythia, privet, or lilac. Can anyone please give me some advice as to these choices or something else that would fill the gap? It is more important to me to have something fill this area fast than look super-duper pretty. Thank you.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Both red-twig dogwood, Nannyberry viburnum tolerate shade. Also Mahonia (Oregan Grape Holly). You might find some informtation here: http://www.colostate.edu/Depts/CoopExt/4DMG/Trees/Shrubs/screen.htm sed5555
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.