Sheeesh. I have to take over all of Slim's cut'n'paste duties while he's gone. Stop asking these questions!
Sun Grown is a term used to describe any tobacco that is not grown beneath shade. Most filler tobaccos are sun grown plants.
However, the term is most commonly applied to advertise wrapper leafs that have not been grown beneath shade.
Typically wrapper plants are sowed and nutured in fields that are tented entirely beneath huge expanses of muslin cloth. This cloth helps to greatly diffuse the sunlight resulting in silky wrapper leaves that are thinner in texture with much smaller veins. These qualities are highly desirable in good wrappers.
Yet in Ecuador this tenting is not needed because its tobacco growing regions are famous for their dense, near constant cloud cover. Here nature provides the shade required to produce beautiful wrapper leaf without the use of any muslin cloth, and in turn the leaves are referred and advetised as being "sun grown."
Basically, all Ecuador Sumatran and Ecuador Connecticut wrappers are sun grown.