if they're that overgrown, I'm pretty sure they HAVE been fertilized. Giving them regular fertilizer is supposed to get you more blooms, hence why I mentioned it. They do better when the water warms up so if we have a cooler summer, you tend to see less blooms. When you repot, be careful of the 'growing' end; it'll have eyes that indicate new growth. Any part that isn't showing this can be cut off and thrown away (if I'm wrong, hopefully addy will see and correct me!). The growing 'tip' should be planted above the substrate. You can even cut off roots for the winter as they'll grow new ones next season. Last fall, I was tardy getting to my leaves and many just froze with the ice. Didn't harm my pond mostly because it's covered and there's not any extra organics to add to the decay list. This year, I have a LOT of leaves so I'll be cutting them all back before lowering them to the deep end.