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.
Adenium obesum, commonly called Desert Rose, is a long-lived succulent plant. It has thickened stems and a swollen base (caudex). The limbs are smooth with small green leaves. The trumpet-shaped flowers are white, rose or pink. Desert Roses are hardy in Zones 10 and 11, and may continue blooming throughout the year.