Originally Posted by Gabe15

I don't think you made any mistake. Any growth that would happen from now on isn't going to add anything significant to the plants, and you may as well wrap them up a little early rather than too late.

But really I don't even think it's growth.

I've had this idea for awhile that when you cut pseudostems and see the resulting immediate "growth", that it's actually not growth. I've always meant to investigate the phenomenon further, but haven't got around to it (yet), and haven't seen any obvious explanations in the literature (though it's probably out there somewhere, I just haven;t looked very hard). The reason I don't think it is growth is that it happens very very quickly, often much quicker than the plant could be growing (sometimes an inch or more in a matter of minutes).

As to what is actually happening, I'm not 100% sure, but my thinking leads me towards some type of pressure release as a result of removing the top of the plant. New growth would seem to be under some pressure as the meristem is dividing beneath at the top of the corm and the young leaves inside are slowly expanding and being forced up through the pseudostem. When a portion of the pseudostem is cut off, that could be taking away a portion of the plant that had resistance to the growth beneath, and like a champagne cork, the result is an immediate and quick spurt of apparent growth of the young leaves below the cut. Surely growth in the true sense (cell division and expansion) is contributing to some minor degree which is probably variable depending on conditions, but I don't think it's the main factor in this phenomenon immediately following the cutting.

I've also noticed the same thing can happen when cutting onions during cooking, and they are definitely not growing. They have a very similar morphology to banana pseudostems.