Flower Color: Lilac Blue Flower Form: Pendulous Racemes Flowering Period: Early Spring Mature Height: 8-30′(3-10m) Pruning Requirement: Prune to Shape Planting Aspect: Full Sun Cold Tolerance: USDA Zone 4 Price Group: 2 About Wisteria macrostachya Blue Moon A vigorous climber for large walls, fences etc. and can be trained into a small weeping standard. Blue moon is the hardiest of all the wisterias. The lilac-blue fragrant flowers bloom up to 3 times during the season. To keep Wisteria in check, it can be pruned in late summer or early fall.