My husband and I went to the Botanical garden in Uppsala, Sweden and the Linnaeus garden last week. Though both are relatively small they were quite interesting to visit. The Botanical garden has a fantastic tropical greenhouse which reminded me very much of Australia, (I grew up in the tropical far northern region which is close to a number of rainforests). Here is some information about the Linnaeus garden (in english) http://www.linnaeus.uu.se/LTeng.html
Cold Climate Nordic Gardening 