That is indeed interesting. Many woods have been tried. During World War II, when briar was not available to the domestic market, various woods and roots were tried in the U.S. and elsewhere. I hadn't heard of the Rhododendron as pipe material. I wonder exactly which part of the bush. There was also some use of the Mountain Laurel, and I don't think that is a different name for the same plant. In that case, there was some concern about parts of the plant being toxic for the purpose, but other parts not. As a matter of fact, there is still at least one carver in North Carolina who still works with Mountain Laurel extensively, though supplies are limited, that being Jerry Perry of Colfax, N.C. to the west of Greensboro. He also works in briar, maple, and on occasions Cocobolo. I've been buying and smoking his pipes since 2002, various woods including several in Mountain Laurel. He does not sell online, but only at the N.C. State Fair in October and the TAPS pipe show in April at the N.C. Fairgrounds. After World War II it became the standard stamp on U.S. factory pipes to say, "Imported Briar," indicating that they could again get briar, and this still appears on a few pipes even today, I think. Burnsville is right there near the Tennessee line in the Mountains on Rt. 19. I think if you could locate one of those Rhododendron pipes, it would be quite a piece of history, as would any lore on the workshop and carvers and marketing of the product. Welcome aboard.