It probably is poisonous to your dogs, Mary. Here's a link to a pretty good website about plants that are poisonous to dogs. Some affect the heart and some affect the gastro areas. It's best to know about them:
http://www.dog.com/dog-article...
I guess it depends on your dogs' plant eating habits, but I don't think I'd risk it.
Wisteria is on one of those lists, I think.
