Daff in Garden

Down one side of my garden in a Cornish Hedge, for those that do not no what a Cornish Hedge is, it is make of rocks built as a dry stoned wall, there are two walls that are filled in between with earth, sometimes there is a hedge growing out of the top. Some of mine has the hedge at the far side and so you can see the earth at the top. 
When we moved here over 20 years ago the were diffs growing out of the top of the part of the hedge and they are still there and this is one of them.