Why do my flowers of Bird of Paradise not open?
My blooms do not fully open and rot before blooming.
Certified GKH Gardening Expert
A lack of phosphorus will also delay blooming. Since a little extra phosphorus will not hurt, I would give the plant some phosphorus, such as bone meal, to help it along. If you have not read it, this article will help you with blooming: https://www.gardeningknowhow.com/ornamental/flowers/bop/bird-of-paradise-blooms.htm
Another possibility is thrips. Thrips are a small pest that typically attacks the base of flowers or new growth. They will kill the flowers before they are able to open. A treatment of a general pesticide will clear them up. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/insects/controlling-thrips.htm