I thought this was wild mint at first but not sure now. Looking a pics of mint and it seems as though the flowers are all on the main stalk and this has the flower clusters on their own stems.
You are correct. I have only found a few of these plants. Supposed to be beneficial for bees and butterflies. Pretty plant but it can become a problem according to what I read. At least it is better looking than all of the horse nettle I have been fighting