I am a big round-up user myself. (well, not actually round up, but the cheaper stuff that has the same active ingredients).
I too hate weedeating. I give myself a nice 10" or so barrier around EVERYTHING. House, decks, trees, propane tank, septic covers, etc.
Once a year is good. It ususally only takes me about 2 or 3 pump sprayers full to o everything:thumbsup: The problem is I ususally have to buy a new sprayer every year though. They dont tolerate diesel fuel well. And I usually find myself using the sprayer with a little diesel/K1 in there to spray down engines or old tractors for degreasing. Whatever I am working on.
And I have yet to kill ANY trees. Including about 30 or so little ones that were dug up and transplanted into the yard from the woods. I also have a bunch of mature white pines and poision Ivy growing up them and all around under them like crazy. I have drenched the stuff. Including what is grwing up the trees. And the bark gets a pretty good dose too. And I have yet the hurt any of them either. But I do mix as the lable suggest and dont mix it too strong.