Floating garden pond plants have hair-like roots that protrude into the water and need no soil at all. These plants certainly assist in keeping water clear since they absorb nutrients from the water and do a good job of oxygenating lily ponds. Water Hyacynth, or the Water Soldier plant are examples of  pond plants of this type.

Floating garden pond plants assist with water clarification. Floating pond plants must however be controlled since they tend to grow rapidly. Some may even be proclaimed as weeds such as the Water Hyacynth in South Africa.

Duck Weed, Water Lettuce, Water Chestnut are typical examples of floating garden pond plants.

Other categories of garden pond plants differing from the floating class can be broken up as follows: 

• Oxygenators as a class of garden pond plants assist in keeping plant water clean and clear by absorbing nutrients. Potted oxygenators include Water Crowfoot, and Water Violet.
• Deep water pond plants the best known of which is the water lily
• Marginal water garden plants such as Iris, and Arum Lily which like to stand in water up to about 15cm (6”). Some can grow quite tall and be blown over by the wind so you may have to weight the pot or crate down with stones.
• Shallow garden pond plants or water garden bog plants like Marsh Marigold, Iris, Water mint. These plants like water about 5 cm (2”) deep and are good examples of pond plants.