I really have no clue about all of this stuff, you already used some bigger words than I can understand smile I let someone that knows a lot more than I do handle our plots...I just know that when a young plant is growing it sure does love sunlight! I think either cutting them high or what CNC said above is probably your best bet, drill and then spray. I know on our plots though, I imagine it would be heck trying to drill thru them as thick as they get, especially this time of year.