5 to 7 years for that one. You can speed it up by feeding it heavily. but only by a few months.

yes it isn't a fast one. As said you'll be lucky to get a flower for at least 5 years. But it is a fun exercise if you have the will to see it through.

That is just a rough guide! I grew Strelitzia Nicolai from seed, and the estimate on that was 5-7 years. It took 11 before the first flower. Every year I would walk past it and say, "Maybe next year". Today, it has several buds coming out, something I would never have if I hadn't started the seed. My philosophy is that if you don't start them, you'll never get them.