I am planting some new species this year but I don't know if they are hardy enoughf for Southern Ontario. They are as follows. Japanese hardy yams Siberian pea tree Desmanthus illinoensis Eleagnus umbellata Salsify
Elaeagnus u.should be hardy to zone 3, And Siberian Pea Tree is native to Siberia, so I would imagine it would do fine as well. I don't know about the others.
EDITed to add: Just looked up the Desmanthus i., and my source says hardy to zones 4-5. Sorry.