The Giant, or Giant White, bird of paradise is an evergreen tree.
According to the 2015 Queensland Plant Census it is sparingly naturalised in S.E. Queensland.
After Strelitzia reginae it is probably the most commonly seen Strelitzia in cultivation here.
The plant suckers easily producing multiple trunks 6 or 12 m high, in dense clumps.
The grey trunk has thin, horizontal scars where the old leaf bases were.
The fan-shaped crown is similar to that of the Traveller’s palm Ravenala madagascariensis.
The leaves, on long thick stalks, can be over 2 m long.
The penniveined (multiple, close pinnate veins) blades tear in the wind.
Axillary inflorescences can have 1 or more bracts up to 50 cm long that hold the flowers.
The bracts are dark blue to purple and each flower can be up to 45 cm long.
Flower structure is the same as S. reginae.
There are 6 tepals in 2 whorls more easily described as sepals and petals.
The 3 sepals are white and the 3 petals are blue.
The triangular seed capsules hold black seeds with a hairy, orange aril.
This is very similar to S. nicolai.
Descriptions I have seen could easily be applied to either plant.
They grow to a similar height and trunks and leaves are the same.
Axillary inflorescences have deep purple or bluish-purple bracts.
Flowers are white and blue and the seeds have an orange or yellow aril.
I have not found a way to reliably differentiate them.
Plants seen in Queensland are probably S. nicolai as S. alba is apparently rare.