Thread:Paul.rea/@comment-78.29.185.253-20140801233944/@comment-4091815-20140802014519

There is no canonical answer.

My guess, based on what we saw, is that Brett was cut when the wolfsbane was fresh while Liam got stuck a day after Violet "brewed" her poison.

But again, this isn't canon because we don't yet have enough info on this species of wolsbane.