They grow outside happily in in my yard... 8b . they are root hardy without trouble. They have been down to 10F for short periods of time, very short here.

Me too...in fact, mine came from seeds via Mara. I sent a bunch of babies to an aristolochian loving nursery owner on the south coast (Brighton Plants) so your seeds are colonising the UK, Mara.

You two have any pics? The one that made it last year for me didn't get to big in it's spot (though set a few seed pods). I was just wondering how big they get.

I have the two native macrophylla and tomentosa growing on my pergola. In the past two years we finally got some of the pipe vine swallowtails visiting. I was raising monarchs inside... so I brought in a cluster of eggs from the pipe vine swallowtail too and try out too. Nothing like keeping an additional 30+ caterpillars alive at the same time. All but 5 or so hatched. The others stayed as chrysalis but looked healthy... so they stayed outside all winter... hoping they hatch this spring.

I grow them outside as a ground cover on my pathway in bright shade under live oak trees. I like the foliage. I love the flowers but you have to go looking for them . A little garden mystery. The vines get around 3 - 5 feet . My soil is not rich nor do they get much irrigation. A grey water outlet is about 5' from them so they do get some extra water. They might get much bigger in a regular garden. They are still under ground for the winter.