Planting Pond Plants
Preparing and planting a pond carefully and a little bit of ongoing maintenance will ensure its health. The ecosystem of the pond involves the interaction of factors such as the water, gases, minerals, sunshine, plants and animals so when these are well balanced, the pond is sure to be healthy.
CHOOSING A SITE
Most pond plants require a sunny position to do well. A site that collects water after rain should be avoided as this may cause flooding into the pond and muddying of the water. An even water temperature is desirable so avoid a position which is subject to cold winds, particularly in spring as this will delay growth. Leaves dropping in to the pond will foul the water so avoid a position with overhanging branches.
FOUNTAINS AND WATERFALLS
The sound of running water is relaxing in the garden and can help to charge the water with oxygen which fish breathe. However, running water is not essential to keeping fish in a pond. Splashing water increases the rate at which carbon dioxide is released from the water and some plants such as water lilies will resent splashing or currents which can often damage the flowers.
SELECTION OF PLANTS
The selection of plants is most important. They provide beauty but also in the correct mixture they will help to keep the pond water clear. It is necessary to have four types of plants – oxygenators at the bottom of the pond, floaters on the surface, submersibles such as water lilies and marginal or bog plants.
Oxygenators
The main benefit of these in a pond is that they grow rapidly and absorb dissolved mineral salts directly through their leaves which would normally feed algae. Including water lilies in a pond to cut out the light and oxygenators to take up the excess nutrients will result in the algae dying and the pond water staying clearer. They also provide a spawning area for fish, a hiding place for fry and food for goldfish. Use the same potting mix as for other surfacing plants.
Floating Plants
Floating plants provide shade and safe hiding spots for fish in outdoor ponds. The plants feed through their roots which are suspended in the water. By shading the water and using the nutrients in it they help in suppressing algae. Fish use the root masses of some floating plants as spawning mats. Examples of floating plants include duckweed, Fairy Floating Moss and Water Lettuce.
Marginal Plants and Bog Plants
Pond plants that stand in shallow water with the pot just covered and lift their stems and flowers above it are referred to as marginals. They are best confined to individual pots that are filled with premium potting mix.
Useful marginal plants include Fishbone Water Fern, Iris Flag, Japanese Iris, Egyptian Paper Plant, Umbrella Grass, Sedge, Sweet Flag, Water Cress and Water Mint.
Plants such as Ajuga, Goat’s Beard, Day Lilies, Ferns, Flax and Mint are suitable for growing in damp muddy positions by ponds
Submersibles
These are plants such as water lilies and numerous other small plants with floating leaves and flowers which can be planted in any vacant spot in the pond. They provide shelter for the fish, produce oxygen and often their beautiful flowers add colour to the pond surface. They should be planted in small pots containing potting mix that is designed for pond plants and covered with a layer of pebbles to ensure that the soil stays in the pot.
Water lilies provide flowers over a long period and also their spreading leaves help to keep the pond water clear by cutting off the sunlight and shading the water beneath. Removing old flowers and leaves every two weeks is advisable. Other surface plants with smaller foliage are Nardoo, Water Poppy, Water Fringe and Water Hawthorn.
INTRODUCING FISH
After the plants have been placed in the pond it is best to allow them at least two weeks to get established. This is particularly necessary for oxygenating plants which many fish will nibble. Goldfish, Comets, Fantails, Moors or Shubunkins can be established in the pond easily after that. Fish will eat algae and insect larvae so they help to keep the water clear and the mosquito problem down.
Koi Carp are magnificent fish but are not the best option in a pond with plants. They have quite specific needs and should be kept in a separate pool to plants.
Aquatic snails may be added to eat the algae however if there are too many they may attack your plants.
When introducing fish to the pond allow the plastic bag they are in to float in the water for half an hour before releasing them. This will allow the water temperature to adjust slowly and minimize the shock to the fish which can make them vulnerable to disease. The pond should be kept topped up so that it is not necessary to add a lot of water at one time which can also damage the fish and plants.
POTTING POND PLANTS
Water plants will need repotting every two to three years depending on their progress. If a plant becomes top heavy or the roots are pushing through the bottom of the pot then it is likely to need repotting.
Potting into a larger container is easy to do and many varieties can be divided up into several smaller pots. Start by removing any unhealthy parts of the plant and remove the excess soil using a hose to loosen the roots if necessary. Place plants directly in to a potting mix designed especially for pond plants. Normal potting mixes are not suitable for pond plants as they are too high in fertilisers that will cause algae in the pond.
Whilst potting, place a pond plant fertiliser tablet into the mix. These will generally last about two months and are easily pushed into the soil. Place small pebbles on to the surface of the potting mix to ensure that it stays secure when the plant is lowered in to the water.
ONGOING MAINTENANCE
Once a balanced ecosystem has been achieved it is unlikely that any major problems with algae will occur and if they do they will be brief. Consequently it is unwise to ‘clean’ the pond out which may destroy the balance. After some years it may be necessary to remove some of the sedge built up in the bottom. If for some reason the pond needs to be completely emptied, it is good practice to retain some of the sedge and original water so that all of the good micro-organisms and other pond life are not completely lost.
