OK,Dave if you are as you say,here is how you win,in the fight against weeds:
-Grow your plants in bush form and let all low branches live so they take all light possible and so weeds will stop growing where there is no sunlight.
Meanwhile now while plants are small use a light duty weed wacker to cut them down,till bushes large enough to kill weeds.
If you insist in one trunk shape you will have to use weedwacker all the time,so it is up to you.
Using Round up does not work because weeds are stronger than any domesticated plant so round up kills your plant first.
My problem here is that round up was used liberally by former owner 30 years ago,and ,it is still impact negatively my soil so much that some plants like (grape vine),grow deformed monster leaves even now after 30 years.
Also round up was sprayed by my neighbour 7 years ago,and spray ,fell on my Wegela which ,was half dead for 5 years and now is back healthy and beautiful.
Edit Note:I am not sure what herbicide was used before by former owners,so pointing it was Round up,might not be true,but according to my lady neighbour who lived here ,from 1964,the former owner used herbicide liberally,and so she warned me not to grow any food producing plant here,but I could not take here advice because I do not have any other land to garden.