Introduction to Pond Fish
Setting up the pond
Plants and landscaping
In addition to enhancing the look of a pond, plants help to maintain water quality, providing a healthy environment for the fish. The choice of plants will partly depend on the style of pond—a naturalistic pond looks best when heavily planted around the edges so that it blends seamlessly into its environment, while a contemporary look may be best achieved with more minimalist planting.
A well-balanced, healthy pond must contain two types of plants: oxygenators (see pp.370–371), which release oxygen into the water, and floating plants, which provide shelter from sunlight. Without these, or an efficient filtration system, the water in the pond can become overgrown with algae, which not only turns the water green but can also affect the health of some fish species, such as Sterlets (see p.359). Plants in the body of the pond also absorb nitrate— the product of the breakdown of fish waste—which lessens the burden on the filtration system.
Incorporating plants into a koi pond is not straightforward, partly because of the depth of water and also because koi have a habit of digging up plants and browsing on the growing shoots. Most koi ponds, therefore, simply incorporate a few tall marginals and perhaps some water lilies, whose leaves help to protect the fish from sunburn in the clear water.
In a new pond, wait several days after filling before putting the plants in place, to allow the water temperature to rise to that of the environment. Pot plants as necessary (see opposite), first inspecting them closely for any signs of disease or pests. In temperate areas, spring is the best time to introduce new plants into an existing pond, because aquatic plants start to grow rapidly at this time. If the pond is large, you may need waders to put plants in place, and special pond gloves should always be worn. These reach up to your shoulders and provide protection against waterborne diseases, such as Weil’s disease (see p.323)—a potentially serious condition, spread by rodents, which causes jaundice.
Edging around a pond strengthens its perimeter and helps to disguise the edge of the pond liner. It can also prolong the life of the liner by shielding it from sunlight. Hard construction materials, such as paving slabs or bricks, laid around the edge of a pond give a more formal look, while natural stone or sod are ideal for a more informal pond. Another possibility is a wooden deck raised above water level, but the wood must first be treated with a nontoxic preservative to keep it from warping or rotting.
Consider the access to the pond: if this is across a lawn, regular foot traffic can quickly result in an unsightly muddy trail. If you do not want to construct a path, set paving slabs into the grass as an informal solution. The planting and landscaping around the pond can be used to disguise pond equipment. An external filter, for example, can be hidden in vegetation in a flowerbed, although it must still be easily accessible for routine maintenance and servicing.
A fountain is an attractive addition to any pond and also creates a healthier environment for the fish by improving the water’s oxygen content. Water lilies prefer calm water, however, and will not thrive under the jet of a fountain, so they need to be located at the opposite end of the pond. Water currents created by the fountain can waft floating plants to one side of the pond; before adding plants, test the flow by floating a light plastic ball on the surface of the water while the fountain is operating. If the ball drifts away from where you want the plants to be, adjust the positioning of the fountain.
- Oriental-style koi ponds often incorporate bridges and decorative features of Japanese life, such as bonsai trees and this popular style of bamboo water fountain (left). Japanese maples create a striking backdrop to the pond and can be grown in pots or in the ground.
- Bridges not only provide an ideal vantage point from which to observe and feed the fish but can also be an attractive and decorative feature of the pond.
- Decorative lighting allows you to enjoy your pond after dark and can also be mixed with other features, such as fountains, to create a striking effect.
- Stepping stones can give a modern feel when made from decking raised on plinths, but make absolutely sure that any wood preservative used is not poisonous to fish.
TIPS FOR CHOOSING PLANTS
- Avoid buying plants in the winter when they are dormant, because it is impossible to tell how healthy they are.
- Examine plants carefully for potential pests, such as aquatic snails.
- Plants already set in containers will grow faster than bare-rooted plants, assuming they do not need repotting.
TYPES OF POND PLANTS
Plants for the pond can be divided into four categories, based on their growing habits and where in the pond they are to be found. Oxygenating plants, water lilies, and floating plants are truly aquatic, growing in or under the water. Marginal plants are a useful addition to the pond, not only as a decorative element but also to provide an excellent habitat for insects.
- Oxygenating plants grow largely underwater, releasing oxygen during daylight hours.
- Water lilies have attractive flowers and large leaves, which provide shade and protection for the fish.
- Floating plants can rapidly spread across a pond, and their growth may need to be restricted.
- Marginal plants can be cultivated in shallow water or boggy conditions around a pond’s edge.
PLANTING POND PLANTS
Marginal plants and water lilies will grow readily in a layer of soil at the bottom of the pond but are most easily managed if they are grown in special planting baskets; this allows the plants to be moved as required, keeps a check on the growth of faster-growing species, and also minimizes the risk of liner damage by invasive plant roots. Choose a relatively large basket, to allow a good amount of space for growth, and fill it with special aquatic potting mix, which creates ideal conditions for pond plants. When planting, never bury the crown of the plant below the surface of the soil, because this will cause it to rot in the water. Oxygenating plants can also be planted in baskets, to contain their growth, while floating plants can simply be placed on the surface of the water.
- Large stones can be added to planting baskets to stop them from tipping over; this is especially useful for tall plants.
- Spreading gravel over the top of the soil helps to weigh down the plant until it has taken root within its planting basket.
- Marginal plants should be placed on the marginal shelf, with the top of the planting container positioned beneath the water level. Raise young water lilies on bricks at first, gradually lowering them as the plants grow larger.
The plants in and around a pond have a great effect on the overall impression created. Traditional, formal ponds often incorporate lowgrowing plants, such as water lilies, which do not mask the crisp, neat edges of the pond. Small ponds often benefit from the inclusion of taller, more architectural plants, such as reeds and grasses, which lift the eye, making the pond appear larger.
- Three varieties of water lily (Nymphaea ‘Escarboucle,’ ‘William Falconer,’ and ‘Marliacea Albida’) adorn this large, formal pond, which is bordered by the tall, elegant spikes of Iris laevigata ‘Variegata,’ Canna flaccida, and Schoenoplectus lacustris. Myriophyllum verticillatum covers one corner of the pond.
- The vertical emphasis of the planting in this courtyard pond, achieved through the use of tall marginals, such as irises and rushes, enhances the geometric lines of this modern style, while a single water lily (Nymphaea ‘Gladstoneana’) softens the look and provides cover for the fish.