I've been looking at a lot of catalogues, in europe and in the US, and what I've seen is that there is only hybrid morus rubras , no true red mulberries anywhere. And isn't that the problem, regarding them? That the morus alba's are faster spreaders and cross pollinate with rubras, so the native tree is endangered.
Now I don't want to turn this into a debate about invasive species, and are ANY species invasive, or just survival of the fittest...but I'd like really to plant dozen or so real red mulberries to my home island in Finland. And yes, that's really not the "native" enviroment either, but hey, there is no danger of cross pollination, since really no-one here grows mulberry, even though it survives provenly here (on arboretum grounds at least).
So how to get seeds/seedlings here? I have really no clue, does anyone?
The first thing to do is find out if there are any restrictions on importing vegetation like trees.
If there are no import restrictions then you should be able to locate several companies that can ship trees to you.
Bear in mind though that some companies do not ship overseas, this is usually due to import restrictions though.
You should be able to locate some nurseries in Europe that have these trees available, Germany, England or France for examples.