I've been wondering about this for a while, ever since I saw thimble berry bushes for sale. @Daniel W posted about his weeds, which made me laugh and wonder about others. My most troublesome to remove and keep away are Mare's Tail, Thimble Berries, Wild Raspberries, Quack Grass, Pig Weed , Daisies ( although I love them they are everywhere and very invasive) , Oregan Grapes and stinging nettle. Funny how many of these I could eat or make tea out of...but they want to encroach on what I really want to eat. What are your weeds that you fight with the most? Or that you would trade off for another if you could?