Dahlia is the most well formed, dense, and colourful flower I have seen in my life. I have tried to grow this with very little success. It requires a cool climate and care.
It is beyond me how nature could have done this. In school we imitated this flower and created paper flowers. Fortunate are those who say these flowers just prolificate in their garden.
They are ideal for creating the most exotic flower arrangments.
Here is a link that has more
Do dahlias grow where you live?