Not having grown it myself, I turned to the Internet for an answer. Do you remember if they've bloomed at all since spring? This source http://www.plantanswers.com/12_mos_xeriscape_/june.htm
says they should have bloomed around May; maybe they're resting now? It also says that the seed pods (like green beans in shape) must be removed for yellow bells to keep blooming throughout the summer. It also says yellow bells needs full sun, but I doubt that not having enough sun would be the reason for all of them to lack blooms at the same time.
My only other suggestion would be to give one of them a high phosphorous, "bloom " stimulant fertilizer- I'd expect that to get you a flush of blooms. Good luck! I hope I've helped.
Hi. My Tecoma Stans blooms about 9 months of the year in Portugal, then dies back completely, and I prune it hard for the winter. I know it is supposed to be drought resistant, but mine is in a large tub, and needs water daily,
How frustrating-- sounds like you're already doing everything right. Now a little bell is going off way down in my brain.
Yellow bells is related to Trumpet Vine, and I've heard complaints about lack of bloom in those. Trumpet vine failure to bloom is said to be corrected by witholding nitrogen, or beating on the plant, by root pruning, or by just waiting for it to get a few years older. The logic in some of these remedies is that blooming is a reproductive function, and when life's too good for the parent plant, it doesn't feel like making babies. Sorry I wasn't thinking that way when I first answered you.
I am having the same problem! I have accused my husband of over watering it...but don't think that is the problem! We have had the esperanza for a couple of years and it has NEVER bloomed! Has beautiful foliage, but not flowers! Would love to hear if you find a "cure"!
The Tecoma that I photographed grew up against the wall of an old mission church. I really doubt it got much in the way of extra water. Things seemed pretty hot and dry the to me an East Coast denizen.
As I mentioned above, Trumpet Vine is a relative. Last summer I saw the most amazing blooming Trumpet Vine. It grew in a square cut out of the sidewalk for a telephone pole. The trumpet climbed the pole . All around is sidewalk, street, and parking lot. Guaranteed no one waters or fertilizes that thing. This is anecdotal, and not the same species, but seems to go along with the 'abuse' theory.
this is out of left field, but could it be possible that the non-bloomers are really Tecoma capensis and not Tecoma stans?
T. capensis is a winter bloomer and has very, very dark leaves and looks much more lush as a rule. if the winters are nipping it back, that would account for the lack of blooms.
other than that, i can't imagine why a T. stans wouldn't bloom...scratching head here.