Though invented by Lovecraft in 1928 [needs confirmation], the name Cthulhu is probably derived from the Classic Greek word chthonic meaning subterranean, as apparently suggested by Lovecraft himself at the end of his 1923 tale The Rats in the Walls.
They're listed as a zone 5-9 plant but as a member of the hibiscus family, Rose of Sharon naturally prefers a warm climate. As a living fence, which is what you really want, you'll be much better off with some kind of evergreen. Juniper, spruce, pine, fir, there are many sizes and varieties to choose from.
Let me share a little background about the plant. Rose of Sharon is a large deciduous shrub or small tree that grows to about 8 to 10 feet tall and 4 to 6 feet wide. The papery, single petaled blooms are similar in appearance to a hibiscus and range in color from blue to magenta to white. Most have a dark eye.