by definition a weed is merely a plant growing where it is unwanted. Many of our roadside "weeds" in the US were potherbs and garden plants for the early colonials. And some of our native "weeds" are ornamental plantings in Europe.

I remember the first time I saw a picture of a highly prized Staghorn Sumac in a gardening magazine from Scotland....as I looked up from the magazine I saw the half acre of sumac my family has been trying to eradicate from the lawn for 2 generations now....mowing, burning, digging it out. Just depends on where it is...

MMario