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I would check for crown or root galls. Here is some information on them that may be helpful: https://www.gardeningknowhow.com/plant-problems/disease/how-to-fix-crown-gall.htm

Yes, you can grow the plant in your area. Here is an article or two that you may find helpful: https://www.gardeningknowhow.com/ornamental/vines/wisteria/growing-wisteria-proper-wisteria-vine-care.htm, https://www.gardeningknowhow.com/ornamental/vines/wisteria/pruning-wisteria.htm

This article should help: https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-blooming-problems.htm

This article will help: https://www.gardeningknowhow.com/ornamental/vines/wisteria/propagating-wisteria-cuttings.htm

The plant could be suffering from crown gall. This article will help determine if this is the issue: https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-diseases.htm If crown gall is not the issue and the vine is still alive and seemingly ok otherwise, I would just give it more time. It may be taking it a little longer to come back after this past, cold winter.

If you are seeing ants, it is likely the plant is suffering from aphids. Ants don't normally bother plants unless there are aphids on the plant (aphids are like cows for ants - they maintain 'herds' to get food from them). Aphids are hard to see and easy to miss and they would explain the decline in the pllant. Treat the entire plant with a pesticide. Neem oil is a good one because it is organic and is systemic. If you spray as best you can, the plant will absorb it and this then protects the whole plant, even if you are not able to get to every part of the plant.