Here is a pic of the trench I dug around my grove to control rhizomes, and what I pruned just today.

I have observed that if left alone, rhizomes will travel at about 2" to 4" beneath the surface. They also like to remain in soil, so when they come out into the trench, they curve downward to try and get back into the ground. All that is needed is to walk around the grove and look for rhizomes 'curving' out of the grove-side of the trench and clip them off.

I used to root prune every fall, but it was a lot of work. I had to go around the entire grove and sink a sharp spade down into the soil. When I heard a rhizome snap, I would have to dig it out... sometimes 3'-4' into my yard, tearing up the grass. The trench is much easier!

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