It's probably still adjusting to your conditions. As for the older pieces that are dying, I would just cut them out. Perhaps the plant since it's division, has just used them as reserves for the adjustment. If it is not spreading, then it is fine, you are doing great with it. I am sure that you will see some blooms on it this spring, every pbulb on my division had bloomed previously, so all this worry will be worth the wait lol. I personally can't wait to see what it does, this plant is really vigorous even though it had condition problems when you got it.
Thanks for the information Nancy, it was helpful to me also
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