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.
About roses of sharon. Rose of Sharon flowers in late summer to fall when few other shrubs are in bloom. Flower colors include blue, pink, red, lavender, purple, and white, depending on the variety. Most varieties grow 8 to 12 feet tall and 6 to 10 feet wide. The plant shows good pollution tolerance, making it appropriate for urban gardens.