Water plants
Water plants (or aquatic or pond plants) can be grown in the home garden, often to great effect. From water lilies and hyacinth to cattails and irises, there is a great variety to choose from. Some aquatic plants can be invasive, so take note of this when selecting your plants.
Buying plants
Plants are usually displayed in shallow tubs at nurseries, especially in spring and early summer. Those are often the best times to transplant, so ask your nursery when they get their stock in or else order online for optimum delivery time. At the nursery, choose plants with a few healthy green leaves. If leaves are small, distorted, yellow or otherwise don't look healthy, avoid the plant.
Planting marginal and emergent plants
Plants for the wet soil bordering the pond should be planted as you would any other perennials. Just make sure the spot is sufficiently wet, and will stay that way. Plastic or cement ponds will separate the water from the surrounding soil, so plants outside the barrier would not get the waterlogged effect they need. Instead, plant in containers placed in the shallower parts of the pond. Otherwise, beyond the barrier, you can plant any regular perennials you like.
Planting in large ponds
In a large natural pond, roots can be planted in the the mud at the bottom of the pond, at an appropriate depth. In an artificial pond, the bottom can be lined with a 20cm (8in) deep layer of topsoil, covered with a thin layer of gravel, and of course water. Invasive plants should be kept in containers in such an environment.
Planting in small ponds
Small ponds under 3m (10ft) wide are best stocked only with plants in containers. Usable containers may be large clay or plastic pots, or homemade containers of chicken-wire holding in burlap, newspaper, sphagnum moss or well-rotted turf. Containers should be filled with fertile topsoil mixed with bonemeal (110g or 4oz per 8 liters/2gallons of soil). Place new plants in these containers at the same depth into the soil that they were in previously, then fill in a bit more soil. Firm the soil very lightly or even better, simply tap/bump the container to settle soil. Finish by topping off with gravel.
Place the container very slowly into the water, allowing it plenty of time to absorb water as it is submerged. Don't plant water lilies so deep (60cm/2ft) that the leaves need too much energy from the rhizome to reach the surface. A pile of bricks or stones under the container to bring the water lily crown to nearly the surface will allow it to gain some strength, then gradually be lowered a layer of bricks per week until the plant is at the bottom of the pond.
Planting in water
Floating plants like water hyacinth can simply be dropped onto the pond water and will begin to grow. Plants that need to be submerged in water may be weighed down with an anchor and dropped so that any roots are held to the ground.
Growing in tubs
Take care to only select a clean tub. Choose no more than 2 or 3 varieties to prevent overcrowding, with preference to smaller, slow-growing plants. In cold climates, the entire tub of water may freeze solid in the winter, so remove any fish during the winter. The tub can be covered with boards and sacking during freezes to help protect it, or brought into a greenhouse.