I don't think there will be any difference. I imagine it's just two seed companies using slightly different nomancature. Hyssop is blue. (Assuming we're talking about Hyssopus officinalis.) or is this Agastache, ie Anise Hyssop?

It is Hyssop, not Anise Hyssop. Although I wish I had some of that, also! :) Thank you. That's probably the reason that I couldn't find anything on "Blue Hyssop".

I thought that the blue hyssop could only be propagated by cuttings. Learn something new every day. I'll Have to do some research.

The standard species can be grown from seed. There are also seed mixtures with pink, white and blue flowers. But when they germinate blue predominates.