This is embarrassing. It’s what happens when you grow a plant that you have never actually observed from seed to dye pot. The Woad I thought I was growing is really Dyer’s Weld. Yellow not blue. More yellow. A really good, clear Lemon yellow but still more yellow.
Before it began to bloom it could have been either.
However, as it blossomed it became obvious that the plant I had was not what I thought it was. Checked every image I could find including the Druid Plant Oracle and I definitely was not growing Woad.
So I’ve got Weld, Dyer’s Weld. Nice looking plant. The bees seem to like it. Works on wool (protine fibers – so not cotton).