If you believe Peter Beales, teas came about either as a result of Chinese hybridizing programs or a chance cross of R. Gigantea and R. Chinensis . While this scenario seems plausible, it is difficult to oppose because these two roses are thought to be extinct. However, Mr. Beales has grandly announced that he has located both of these roses in Bermuda. That contention has not yet been proven out. One of those roses fails remontancy in warm climates, disproving its China origins.
Teas are wonderful roses for a number of reasons.
One is color. Flowery language perhaps, but accurate. Peter poo-poos the scent as smelling like freshly opened tea boxes. Perhaps teas' biggest plus is the length of the flowering season. They flower virtually all year here in California.