This flowering shrub was seen in a hedgerow in Dorset. It was the only one there so I wondered if it's a cultivated plant that "escaped".
Crysanthemum, perhaps? How big is it? What are the leaves like?
It was a bush about 3 foot tall
Nope, not crysanthemum!
Perhaps could be Tanacetum parthenium 'Pleniflorus'
Yes, that looks good, thanks