I am not sure whether this is actually a Himalayan Trillium, that is what it was called when I bought it. It does look similar to photos I have seen of Himalayan Trilliums but it is a lttle different. It does not spread at all each bulb sends up one shoot every year. It then blooms ( just what you see in the photo) in the spring. It will keep its green leaves until the fall unless it is really hot and dry. It is planted under a Japanese Maple and also shaded by the Hellebores.
I need these plants
9810067546
http://www.heronswood.com/perennials_perennials-p-to-r_paris/paris-polyphylla/
Plant Delights in North Carolina is still listing it but I have never done business with them.
http://www.plantdelights.com/Paris-polyphylla-Perennial-Multi-leaf-Paris/productinfo/9313
It is native to the Himalayas, Western China, and southeast Asia.