Earlier in the year I bought some Red Sunflower seeds from a shop called Premier Seeds Direct, off Ebay.
I planted some, along with some sunflower seeds picked from the hamster food. Both types of sunflower sprouted, but the red sunflowers grew the fastest and so far are the only ones to flower.
Both the above flowers were grown from the 'red' seeds. Some of the plants have multiple flowers, such as the one on the left where several smaller flowerheads are visible.