Just Joey isn't a prolific bloomer to begin with but only 5 hours of sun may be the problem. Roses need at least 6 hours and prefer 8 hours of direct sun to perform their best. Lack of bloom is one of the first signs of too little sun.

How long is "long stems"? If they appear stretched, too little sun is likely the issue. Mid day, SoCal sun is best now at around six hours. Much more, and during the worst of the worst, the plant can struggle just to remain alive, depending upon how far inland or how high in elevation you are. The closer to the cooler, damper, foggier beach you are, the more sun it can endure. The more "valley like" your climate, the less it will successfully endure. I'm in Encino, just over the ridge from Brentwood/Beverly Hills. Eight hours of mid day to afternoon sun has fried foliage and new growth this summer. More shade from buildings and overhanging trees resulted in better foliage, more flowers and less radiation/heat damage. Kim

I was wondering if Just Joey is a finicky rose. I had one on it's own root and it never did anything then just died.

Compared to many HTs, Just Joey is not "strong growing". It was selected, introduced and only sold budded to the traditional stock in Britain. It wasn't until the US got hold of it that own root plants became standard. In a British type climate, with sufficient rainfall and budded on a stock suited to the climate, soil and water, it's acceptably vigorous with a sufficiently beautiful, scented bloom to be worth many peoples' trouble. Own root, where it is marginal, it is stingy and weak. I love the bloom and prefer it to Brandy, it's closest American "rival" of the period. But Brandy is a much more vigorous, easier to grow and more heavily flowering PLANT in my part of the country than Just Joey can ever be. Kim

My JJ blooms as often as most of my HT's. , but it is a gangly branched thing. Here it is ( about 6-7 years old) with lots of buds that will be lovely....just too late for the party that I cut it back for. Ah well. Cut back several in Oct., just a little too late. He did not bloom as well this year in our hideous heat. Can only think I didn't hand water enough, and the sun was too hot at times. I'm in so. Ca. coastal/ 6 hours sun. I adore the sweet scented , big apricot blooms. Poor pic trying to get all the many little buds in the pic. I'm betting these blooms will not be so large. Is it the cold nights? I see this often in my autumn blooms. Still, my neighbor's bed faces west, and hers are summer- lovely. My sun is eastern. Well, that's another topic.
JJ is worth your patience, imo. Good luck!