Hi Nancy... there are two downsides to wisteria.. the vine is very strong and wraps itself around it's support system so strongly that it can pull it over... the column you see on the front corner is actually leaning off center. Because of this, we have to prune it back about 3 times a year, cutting branches that that become too large. Make sure you have a very strong supporting frame. The second downside is the root system which trails along the base the of the plant. The trailing roots are shallow so they can be pulled up easily as long as they're small. If I were to plant a new one, I would bury 18" deep plastic boundary around the root system to keep it from trailing.

Some may consider the dropping of the blossoms and the pods to be a downside, that doesn't bother me at all.......that's what brooms are for!

In the end, I love this plant.... when the flowers pass, the greenery fills in creates a private room underneath this pergola... we can actually sit outside in the rain and stay dry.