I have these plants popping up all over my 10x10ft garden in Wisconsin. I think it may be some kind of flower. I think the leaves look like potato leaves. I want to know what this is. Is it a weed?
That is an amaranth, Amaranthus sp. This is a very common weed in the temperate U.S.. For control and uses of this plant, refer to this question: What is this fast growing plant and should I rip it out?