In doing a Google for both of them I see I have been misinformed for many years. They are 2 very different plants. Jewel Weed is an impatient or balsam. Black Nightshade is in the same family in family as tomatoes, eggplant, etc. and is called Solanum Nigrum. The plant I have been told is Blk. Nightshade that is often devoured by blister beetles and I suppose Japanese beetles. I let it grow in limited number and don't see any Japanese beetles. I don't know if it kills the b.b.s because there are so many of them that hundreds could go off and die or be eaten by birds of many kinds & I wouldn't know it. I also spray b.b. when I see them just to be sure they die. They will strip potato plants in no time.
I hope this helps you.
