Pastor Todd Weir knows a lot about weeds. He says: I learned more about weeds than I ever wanted to know as a boy in Iowa.  Walking through the soybean feels to cut out the weeds was my summer job from age 13.  A wise farmer once taught me that all weeds were not the same and could not be destroyed in the same way.  A cockle burr had shallow but widespread roots and had to be pulled out to get all the roots.  If you hacked it off at the ground level with a hoe it would be back in a …