Just added a flower painting to my portfolio

Lily Dream – Watercolour - 11”x15”

Lily Dream – Watercolour – 11”x15”

This is a painting where I had a lot of fun experimenting with a new technique I found to create the patterns in the background. Can you guess what material I used to do this?
If you have any tips or techniques to create texture and interesting marks in paint please feel free to share them.