Flowering quite rare in French Guiana (this individual flowered just once in 10 yrs!). Flowers open a few minutes after nightfall and wither at dawn. Powerful scent reminiscent of Hyacinthus orientalis. For phenology see detailed observations of anthesis:
https://www.inaturalist.org/observations/214046487
https://www.inaturalist.org/observations/214046488
https://www.inaturalist.org/observations/214046490
https://www.inaturalist.org/observations/214046492
https://www.inaturalist.org/observations/214046495
https://www.inaturalist.org/observations/214046500
@theo_damen