I\'ve girdled a medium size Mulberry with 3 trunks 3ft. from roots and plan to remove any new growth in the future, my question is how long will the tree produce the new growth?
If your goal is to kill the plant, girdling usually takes place closer to the ground. You will have new growth the entire 3 ft to the ground and probably some suckers as well. I suggest immediately applying glyphosate or triclopyr to the fresh stumps of new growth. It just takes a drop or two. I apply with a small foam paintbrush. To avoid herbicide use, you have to keep pruning new growth every few weeks - I'm guessing here - throughout summer and fall to exhaust the root system. Allowing leaves to stay on the plant starts to rebuild the roots and prolongs the process.