Beware Yellow Rhododendrons
Some of the Northeast nurseries are selling R. hotei. If you have hot, humid, summers like I do, Philly area, I wouldn't waste time with anything that has R. hotei in its genes if I was looking for a rhodo for landscape purposes. I've been looking into some of the yellows, like Top Banana, Papaya Punch, Nancy Evans, a few others. These are all hotei hybrids. Lost papaya first season, top banana wilts a branch every month or so. I once tried three plants of hotei; lost all three in one season.
Have had better luck so far with My Jane, but this has less yellow than hotei and its hybrids. Nice huge truss though. However, I've had it for a few years and it seems to be losing, not gaining vigor. Never tried Capistrano, but have been told of problems.
This year I got Evening Glow: fortunei ssp discolor x Fabia Group. Unusual in that it blooms late. June here in Philly. Good yellow. No wilt this summer. Keeping my fingers crossed. Might be something to work with.
As for rhodos like Unique and Goldfort, great plants, but not really yellow. Sometimes when viewed though certain light they can give the perception of yellow; If that is enough for you, then you might want to get Unique before wasting time with any of the "true yellow" rhododendrons, or just just say the heck with it and get the decidous azalea Klondyke, a real head turner and easy to grow.