This genus intrigues me, vining fruit in general seems uncommonly grown except for grapes and a handful of other; they can add another layer to the garden.
My understanding is they are dioecious. I have heard Kadsura is growing successfully in Australia. It seems to be all over the Asian continent, Japan, China, Indonesia, etc, so cold hardiness could be a species specific trait and there certainly doesn't seem to be that much information out there yet. Generally I have herd they are cold tolerant, but not sure of the reliability of that information.
I also purchased the same species on eBay from Thailand I think as well as some other species from Trade Winds. Trade winds recommended cold stratifying, so I did a some stratified and some not. There was some delay in getting my germination set up together, but I set several of those seeds last month. I planted them just under the soil and a sneak peak revealed germination in the coccinea but it has not yet broken through the soil so we shall see.
I purchased a few more mature specimens of unknown species from another member earlier this season. He said they were 2 years old. Very small for the age, all well under a foot. They have grown for me slightly, but look similar to when I originally purchased, alive but not thriving, they only hold about 2-3 leaves each. Previous posts on this site have had conflicting information, some have said they are quick growers and others have similar experiences with the plants that I purchased.
Hopefully we can figure out more about this species together.