Don't actually know but it could be down to the temperature not getting high enough. One of my colleagues has one and it lives in the conservatory all year round and usually flowers late summer after it has had a hot spring/summer.

I know that they can take some time before they begin to flower and need a sunny aspect. I would try and only use a high potash feed but sparingly as a general feed can encourage lots of leafy growth as the expense of flowers.

It isn't the heat. Missouri gets a lot of heat in the spring and summer. If it was from a division, they can take up to 4 years to flower, and one from seed will take around 7 years. My giant one took 11 years.

I had one for four years which I placed in front of the patio doors, it didn't flower so I gave it to a friend they placed in front of their patio doors and it flowered the next year. I think that it just takes a few years to establish and when it is happy then it will flower.

thanks for the encouragement. time may be the answer, however the original plant is about 20 years old and the division probably 5 years. I will admit that they have only received the extra fertilizer and water for the 3 or 4 years. maybe next year.

Sometimes a little neglect will put it under stress and it thinks it's going to die and suddenly puts out it flowers to seed and produce its successors.

They bloom best when the nights are long and the days are short--in short, in the winter and early spring. In your case, that is the time when it is indoors, and getting less light, and probably longer "days", due to artificial light.