Some particular varieties are extremely hard to get to bloom. Not enough light, too much light, not enough water, too much water, fertilizer, yada yada. Could be almost anything. Temperature typically plays a role but again depends on the particular species. Hopefully soon! 15 years is long enough.
I'm waiting almost 15 years for one to bloom, I know it is super healthy, flowered years ago, soon hopefully!
Some particular varieties are extremely hard to get to bloom. Not enough light, too much light, not enough water, too much water, fertilizer, yada yada. Could be almost anything. Temperature typically plays a role but again depends on the particular species. Hopefully soon! 15 years is long enough.
It bloomed in a neighbours garden, then moved all that time ago has grown, never flowered I remain hopeful it is the best I can do.