Increasing Aquatic Plants by division of from cuttings isn't really that difficult if you take the time to learn the basics.

In the spring, division can increase almost all-aquatic plants. You are taking the crown of the plant and dividing it into two or more pieces, which will be potted separately.

Marginal plants like the Rushes or cattails have a creeping root system and all that's involved is removing part of the rootstock to start another plant.

Your Iris, water plantain and marsh marigolds can simply be pried apart and replanted in another container.

The Root Cuttings

If you would like to increase the number of bog type plants, you can simply take root cuttings. You should, however remove all the root cuttings during the dormant season. Then just return the full-grown adult plant to the soil in which it came. Select the root cuttings that are about the size of a pencil to start. Take pieces about 1" long and place them horizontally in trays of good soil mix, cover them with more soil and water thoroughly.

The Stem Cuttings

Most of your marginal and bog type plants are easily dividable, however they do much better propagated from stem cuttings. Select non-flowering shoots, about 2" in length, wish you should remove from the parent mature plant in late spring. Place them in a pot of sandy loam and submerge them in water. Rooting should take place in about 10-14 days.

The submerged plants are easily increased by just taking stem cuttings during the height of the growing season, usually summer.

Waterlily Eyes

Most of your waterlilies are best propagated using the "eyes". These are just tiny growing points that occur around the rootstocks of the mature plant.

Adult Hardy lilies should be taken out during the early summer and remove the eyes with a sharp knife. When you cut them off, the wounds of the rootstock should be dusted with powdered charcoal to reduce the risk of any fungal infections. You can now plant the eyes into small pots or trays, using a soil-based mix and stood upright in a shallow container. As they start to grow, they can be transplanted into a larger container and deeper water until large enough to place in the pond