I've had a few throw multiple stalks from one rhizome.....for me, Clarence does it quite often, and Belvi Queen *sometimes*. I'd always felt it was a response to the extra fertilizer, and water..but that's just a guess, on my part
. As to cutting the extra stalks....once they've started...cutting won't" save" the stalk until another year, but, it *might* conserve enough energy to help shoot a few increases. When I have one that blooms, without increase, I cut the stalk about halfway up, so I don't damage any of the leaves, and give it just a "touch" of 10-10-10....maybe a teaspoon full, as close to the rhizome as I can get it, without actually touching it, and make sure it stays 'damp"....if the soil gets dry to the 2" deep level....water it.....and they almost always will start a few increase.