How much sunlight does a sunflower need?

How much sunlight do plants need? Well it all depends on the plant. Hostas, ferns, Impatiens & Hemlocks thrive in the shade while succulents like cactii and Aloe Vera need lots of southern sunlight all day. Most flowering plants need at least 6 hours of direct sunlight/day, while lawn & ornamental grasses need full sun all day. Plants use sunlight to convert nutrients from the soil & air into sugars used for energy through a process known as "Photosynthesis"