The sunflower stands for many positive things. For example, in a German book about the language of flowers from the 19th century, it says about the sunflower:
«Where you are, I want to be too - as with sunflower and sun». So, the sunflower is the symbol of fidelity here, because it accompanies the sun from morning to evening.
But of course, sunflowers also look like little suns. For this reason, in their original homeland of America, they were considered a symbol of the sun gods.
Even worldly rulers claimed the sun symbol for themselves. The Sun King Louis XIV, for example, even had coins minted with sun and sunflower at the zenith of his power.
Moreover, the sunflower was also a symbol of the hippie movement in the 1970s.