Cool ! I think it's ok to send those.
I've tried Caesalpinia Pulcherrima but the same story.
It's the dry light overwintering that's the problem.
I have a Caesalpinia Gilliessii outside in a border, and amazingly it's done three winters so far.
All I do is cover it up, leaving a clear bag at the top so light gets to the shoots.
It hasn't flowered yet.
I live in hope, with it having a bigger root run- all the info I can find from places like Florida is that it won't flower in a pot....
I've never managed jacaranda flowers either, but they only flower on last year's growth, so the damn things have to be bigger than a greenhouse, and the fact that they make a right mess doesn't help.