I will admit I am confused by the naming of this one. I have been open about lacking knowledge when it comes to plants and flowers, so I assumed dahlia would be green in colour, or at least some of the variants. I looked at 12 pages, some 220+ different plant options on the Royal Horticultural Society shop website, and yet the closest I could find was the Tsuki-yori-no-shisha below and that is probably a cream flower with the green being a reflection of the stem. Fortunately a further search showed me there were green ones out there, though not available for purchase in the UK. I did ask a friend who is a keen gardener and he mentioned dahlias do come in every colour bar blue, however the green ones tend to have very little contrast with the foliage around them.