Is there anything that can be done to make my Japanese wisteria bloom?
The Japanese wisteria (Wisteria floribunda) is the most widely grown wisteria in the United States. Unfortunately, it doesn't perform well in Iowa. Most Japanese wisteria varieties (cultivars) do not bloom when grown in the state. There is nothing that can be done to force Japanese wisterias to bloom.
The Kentucky wisteria (Wisteria macrostachys) is a better choice. Though its flowers aren't as showy as the Japanese wisteria, the Kentucky wisteria blooms reliably in Iowa. Excellent varieties are 'Aunt Dee' (light purple flowers), 'Blue Moon' (light blue flowers), and 'Clara Mack' (white flowers).