Helianthus annuus, a bright yellow sunflower, is the symbol of summer. They normally start flowering in mid-summer and can continue into the beginning of September. The flowers have a broad center disk encircled by short petals, and they range in size from 3 to 6 inches across on average. The primary species plant has petals that are orange-yellow with a brown or purple disk, although growers have recently created flowers in a variety of various hues...