Seeing which colours go together (dahlia in pot).

Lol!....not only me that does that then! Look how vivid they make each other.......

I put some Osteospermum Sunny Shiela with these plants last summer - similar colour to the dahlia and the result was amazing. Can't find any this year but got some plug plants which are rather small and probably won't flower in time.

That blue geranium really sparkles alongside your beautiful Dahlia.