Spring is a great time to lift your hardy water lily out of the pond, (leave your tropical water lily alone until December when you will need to fertilise) expose the rhizome and cut back about 10cm from the crown of the plant.
Discard the excess woody rhizome and root system. Position the newly cut crown of the plant into a quality water plant potting mix, fertilise with 2-3 mantuec slow release water plant tablets, place heavy gravel on top of the pot (to keep the soil in and the fish out), then soak in a bucket of water for about 5 minutes. Then place directly onto to base of the pond.
If your water lily does not require re-potting, it will definitely benefit from fertilising. Just push the pellets as deep as you can into and around the growing tip of the lily.
Article published in Garden Guru Magazine Spring 2009