You should be able to send them in the mail. Get a start like you did for your garden. I am assuming it has roots? If so place them in a baggie with some soil to protect the roots and wet it to keep it moist during mailing. Seal the bag around the stem and put it in a box and send right away. Oh and I would put some shredded newspaper to keep it from getting tosseled all over the place.
I don't see why that would not work. I am going to have to look up passion
flower and maybe I will beg you for some too!