9/14/2017 9:09 AM
My advice is find someone that has one or purchase an Imants Root Pruner. They run about $12,000 but will allow you do do the entire course every few years.
I went to the Great Southern Tree Conference a few years ago that was put on by the University of Florida. Dr. Ed Gillman had a particularly interesting on-going research project that was about 20 years in the making. He actually looked at all kinds of barriers from the ones commercially available, to concrete walls, to galvanized sheet metal, you name it. During the session, they had air excavated each barrier so we could see the effectiveness. His conclusion was that in each case, eventually the roots make it under, over or through the barrier at different lengths of time. Since seeing this, we have steered clear of the barrier and have done the every few years approach. With the Imants Root Pruner, it's a one man job that is very quick and zero clean-up. For instance, we had a contractor out that did both side of every hole tee to green in about 9 hours for $1,500. He's since been back and did it again.
I would also suggest going as close to the tree as you can. In some cases, we were about 3' off the trunk. Hurricane Irma just blew through with 80+ mph winds and none of these trees blew over.