Why is my devils club tea green?

So a friend took me the other day, to my utmost joy, to a wonderful little forest glad where there was a splendid amount of young devils club. i have been studying medicinal plants for a little while now and was very excited to be harvesting for the first time devils club, as it is renowned for its medicinal qualities. So i carefully gathered as much as my little pack would allow and took it home stripped off all the spines down to the green inner bark and then stripped off the inner bark and dried it. Today i made my first cup of it and at first it was the expected yellow most teas are but then it turned and bright lime green......is this normal and alright?