I have seen some weed that has a blueish tint to it. My bud is growing some outdoor stuff and we noticed a blueish tint on the edges of his leaves. We thought it was weird cause in all his and my years we never saw a blue tint. The bud was killa when it was finished though. Im not sure what your guy meant by "blue weed". Maybe he meant blueberry?

Happy Toking :rasta: