Which one? ;o) I assume the yellow one but I cant get a decent view on this computer.
A close up of the flowers would help too.

the pale pink/white one looks like Hesperis matronalis [sweet rocket]. There appears to be a nice allium in there too.

Sorry the tall acid green one in the middle

the closest I can get it to is possibly a crucifera ie a member of the cabbage/cress family or a Crambe which is in the same order
.
I cant see the flowers clearly enough. was it deliberately planted or is it one of mother natures gifts?

I will remember think i got from special plants

its woad, i ve just seen it in the physics garden at Cowbridge. i knew i recognised it but couldn't drag it towards my memory.

Yes would have never got that well done! I remember it now have tried growing it from seed before with no luck germinating it (seed sowing is hit and miss for me ) so it could have been a seed that finally germinated!..... I also bought it as a plant after failing to get it to germinate by seed but it just wasn't happy and faded away eventually after a couple of years without flowering in my clayish soil maybe this was a stray seedling quite a fussy plant which must have free draining sandy soil and full sun