We are located in northern Mongolia in what is probably a Zone 2 to 3. We have hot, dry summers and usually cold, dry winters. The summers are ideal for short season grapes, if you can get them to survive the winters. I started growing V. riparia , commonly known as Riverbank Grape, from seed that I got from Saskatchewan. I planted the resulting seedlings outside on the south side of my house and in our greenhouse. In both situations, due to our lack of snow cover, I had to lay the vines down and cover them. The vines started flowering in the 3rd year. Three years ago I got some "Concord" cuttings from Regina, Saskatchewan and I got some Vitis amurensis seed from Russia. It is native to the Amur River valley in Russia and China and reportedly can take -45C temps (with snow cover). The Concords started flowering and fruiting the second year, but again they need cover in the winter. The V. amurensis are growing well inside and outside the greenhouse but also need cover in the winter. Reportedly they start fruiting at around 5 years and they color beautifully in the fall. All three of these varieties would do well in a Zone 4 climate, especially with decent snow cover like you usually have in Ontario. The V. riparia and V. amurensis are both aggressive growers and can take hard pruning.