We have a laurel hedge on one side of our property that we want to with replace with native bushes. To maintain privacy we had planned to cut it down when the natives (pacific wax myrte) reached 6 feet but they are growing much slower than they should, despite adequate sun and water. I suspect competition from tge laurel roots. If we half- girdled the laurel trunks - on the wax myrtle side would it stop the branches roots only on that side? Photo shows 3 year old myrtle is 3 feet and laurel is 9. We've been trimming laurel to 8 feet and away from the myrtle but hadn't done so yet this year.