Howea fosteriana - Kentia Palm, Strelitzia nicolai - Giant Bird-of-Paradise

I have 2 bird of paradise plants in my garden. Both seem healthy but NEVER flower. I've feed them; repotted them; talked to them. Given them lots of water; not given them water but , alas; they still refuse to produce flowering stems

Maggiski:

Is it a Giant-Bird-of-Paradise (Strelitzia nicolai) or Bird-of-Paradise (Strelitzia reginae)? If it's a Strelitzia reginae...it needs short days to initiate blooming.