Water lilies grow abundantly in water gardens and ponds. These aquatic plants form large under water root systems called rhizomes. The rhizomes produce "eyes" that become new stem and flower systems. Each eye can be divided from the root ball during propagation to create a new plant. A large root ball can be divided it into as many as 20 or 25 new plants. The earlier in the spring you can propagate your water lilies the better, that way they have the long hot summer to establish their new roots and growth before winter.
Pull a large water lily plant out of your pond or water garden by grabbing the underwater pot the lily is planted in and pulling it out of the water. You might have to get wet to do this.
Gently remove the root system from the pot and lay it on the ground or table where you intend to work.
Select sections of the rhizome that have new green "eyes." Divide each large root system into as many new plants as possible with one "eye" per new plant.
Use a very sharp knife to cut the water lily rhizome into new sections. Using a dull knife can mangle and damage the root system.
Look carefully at your new root sections and carve off any damaged or rotting tissue that you find using a sharp knife.
Line your planting pots with rough cloth or sack material. Use large enough pieces that you can fold the top of the cloth over the pot after the new roots are planted.
Fill the pots half full with aquatic soil. Aquatic soil can be purchased at most home and garden stores. It is preferable then regular potting soil as potting soil could stimulate damaging algae to grow on the new plants.
Place a divided root section in the planting pot and cover the root with aquatic soil leaving the green eye exposed.
Fold the cloth sack over the top of the pot and put a few pebbles or small rocks around the edges to prevent the plant from floating away. Leave the "eye" in the center uncovered so that the new growth will not be hindered.
Place your new plants in a shallow sunny part of your pond or water garden making sure that the pots are fully submerged.
After the new plants get established in the shallow sunny area for a few weeks you can move them to deeper water or to their permanent homes in your water garden.