I would say no!

I'm not aware of blue being in the genes of the sunflower. usually yellows oranges and reddy browns,

Agree with Drc and SBG no such thing unless, like the heathers, someone is dying them!

Ugh! Both blue heathers & sunflowers.

There are no natural blue sunflowers, but if you cut them and put them in a vase of water with some blue food colour in the flowers will drink the dyed water and turn blue.

they'd end up looking green blue veins against yellow pigments. Either way not a good look :o)

Agree SBG!