My White Bird of Paradise plants sure do look different than what I see in those photos,
@GraemeP. I have nine of them, 7 in the ground (most are in all-day sun) and two in pots. All my plants were started from seed and they are now approximately 18 mo. old. One of those potted plants is in the screened-in lanai. Those potted ones are sort of experiments, just to see what happens with them. None have bloomed yet, and all the plants are 4-7' tall. Oddly enough, the two still in pots have grown larger than those in the ground. That's probably because my potting soils are custom made and thus, have more "goodies" than the soil (even though I amend the dirt when planting).
Strelitzia nicolai in pots
Strelitzia nicolai in the ground