Posted: 05/04/2012 at 22:28
Ok - are you planning to dig out the existing hedge or have the hdege cut and the stumps ground out? I think it will take a great deal of effort to dig out the hedge - if you can get a vehicle to pull the plants out it might be a lot easier. Any way, once the hedge has been removed, you will have to do some work on the soil before replanting. All the goodness will have been removed by the previous hedge and it will probably reen]mble dust. You will have to dig in lots of organic matter - compost,, rotted horse manure etc in order to give a new hedge a good chance. You will also have to feed and water it well for the first year or two. While the new hedge grows you could put in some hurdles to give the hedge some shelter (if it is a windy site) or give you some instant privacy.
I am afraid I have no experience with cedar but my neighbour has planted a yew hedge which is very thick and beautiful. He let it grow until it reahed the desired height before trimming the top and only cut back side shoots the came out too wide in order to encourage more side shoots to branch. A hedge is only green on the outside, not in the middle.
Hope this answers some of your queries.