Paris polyphylla var. yunnanensis
One of the stars in our shade garden is this Chinese Trillium relative. We find this eminently superior to the typical Paris polyphylla typically offered. These are seedlings from our garden plants which are marvels of vegetative increase. The 3 bulbs we originally planted 8 years ago have now increased to over 50 stems up to 40" tall with elegant flowers and showy orange fruit. Hope this kids have learned something from their folks. These might flower next spring as a few did flower this year and some of these young plants are already starting to differentiate into multiple growth buds.If you are ordering this as a dormant bare root bulb, it is fine to plant it outside now (assuming the ground isn't frozen etc) as these have been growing outside here at the nursery. Three inches deep should suffice and if you live in harsh winter climates, a good mulch will help. These come up late in the spring for us - later than other forms - so don't worry too much. They like an acid soil, moist yet draining, and we expect that if you can grow Trilliums successfully, you should succeed with this one. Zone 6 for sure and probably into zone 5 although we have no personal experience with it in those regions.