The neighbor two houses above us had a 30' Tacoma tree planted in the sidewalk area of his property...Problem was, he never raked the leaves...The prevailing winds are downhill so all his leaves ended up in the neighbor's yard above me with the residuals ending up in our yard...
After 20 years of this sh*t...the tree died... Seems my immediate neighbor, bore 8, 1/2" dia. x 8" deep holes in the base of the tree, about 2" below the dirt line and poured concentrated Round Up into the holes...Took 3 weeks to do the tree in, after only one treatment...
When's your neighbor going away on vacation? May be a good time to buy some Round Up....
Aloha! Mike