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.
Give this evergreen shrub moist, well-drained, acid, organic soil. In the South, site it in shade. USDA Zones 4b to 7. The so-called Christmas rose is actually a hellebore (Helleborus niger), and for areas of the country where winter flowers are a rarity, hellebores are a delight.