Wild Yam in Switzerland

I thank you very much for the Herb Catalogue 2001.
Going through it I found the Wild Yam, Dioscorea villosa (page 56, S6995). Studying the possibilities of purchasing I saw that you offer Root cuttings. This means also that we could plant them. Now I do not quite understand Z4-8 Zone. Can I plant this root also in Switzerland. Climate is a bit milder than Ontario. I used to live there that`s why I know the climate.

In the Richters InfoCentre section of our website you will find a hardiness zone map based on the USDA zone system commonly used in North America. Much of Switzerland is shown as zone 7, although alpine areas will be lower.
Southern Ontario ranges from zones 4 to 6. Goodwood, where Richters is located, is zone 5. So your comment that Switzerland is a "bit milder" than Ontario is consistent with the USDA zone ratings.
Because wild yam is rated hardy from zones 4 to 8, it should grow well for you in Switzerland.

I also would be interested in Eclipta (page 19, S2288)

Eclipta is an annual and you should have no difficulty growing it.