I wish to plant new hedges or shrubs in my hard to assist in the privacy of my small NY City yard. I have an area about 12 feet long that I want to fill with a "green fence". It gets plenty of sun, but I want something that will reach about 6 to 8 feet, but I dont want to wait 5 years. Any suggestions on a fast growing plant that will make that fence like barrier, not cost a fortune while filling in the back property line like a fence?