Are they any North American sundews that I can grow outside year round in Wisconsin?
Tropical Fish Enthusiast
D. rotundifolia, D. intermedia are two - but you will need to mulch / insulate them.
I highly recommend Drosera anglica. *I found colonies of this plant growing in areas of the mountains that can get -50F in the winter. *The plants that Jim mentioned are also good. *One thing to take into consideration is the location where the plants originate. *For example, D. intemedia grows in South-eastern U.S., Northern U.S., parts of Europe, and there are also tropical forms. *Try to find plants that originate from the coldest regions.
A good place to get seeds is the International Carnivorous Plant Society. *Some good canidates from their seed list are: *D. intermedia from Germany, and D. anglica and D. rotundifolia from Alaska. *I have all three and they do just fine on my sunny deck.
I would also recommend seeking out some natural bogs in your area during the spring. *You should find S. purpurea, and all three of the listed sundews. *A person can learn a lot from observing plants in their native habitat. It will be a great experience.