Water Gardening:

A water feature in the garden is the ultimate in flexibility. It can be small

or large, still or moving, and include plants, fish and other aquatic life,

 or neither. It can be elaborate or simple, and as  much or as little

work as you choose to make it.

 A water garden does not require any special gardening experience, and generally succeeds under the most trying of conditions as severe heat or even drought have minimal effects upon it. Many water enthusiasts begin with something as simple as some type of water fountain, and this may be all that is desired. Others may wish to have a small pool of water, either in a container or dug into the ground. If you choose to use a container, your options are almost endless… plastic containers of all sizes, lined pots and barrels,  preformed ponds, old bathtubs or “kiddie pools”, and even swimming pools have all been used for this purpose. As you may expect, the larger your container, the more options become available in terms of gardening potential. 

A water feature that is expected to have both plants and animals (fish) needs a few essentials in order for it to be successful. These are listed below, in no particular order, with examples:

• Oxygenators- underwater plants that absorb excess nutrients from the water and provide oxygen during the day, which helps to clear the water and prevent the growth of algae  that causes green water. They also provide spawning space and shelter  for fish and other aquatic animals
  • Elodea canadensis and hornwort (Ceratophyllum demersum) are both hardy in our area.
• Floating plants – these plants do not require planting and help control algae by shading the water and using dissolved nutrients. They also provide spawning areas for fish.
  • Water hyacinth (Eichhornia crassipes) are annuals that every pond should have.
  • Duckweed ( Lemna minor or  Lemna trisula) are both hardy, provide fish food and help to clarify the water.
• Water lilies – hardy and tropical – grow quickly to provide coverage when given the proper conditions: sunlight, warm water and rich soil and nutrients. Every pond should have a least one lily, and with the wide variety of size, colour, and ease of culture, the greatest difficulty is often deciding which ones to choose.
• Shallow water plants – at the edge of a natural pond you will find a variety of marginal plants. Although not essential, they help to make the pond more attractive. There are a  wide variety of hardy plants available, including iris, rushes, arrowheads, sedges, sweet flag, water forget me nots, and of course, cattails. There are many tropical plants also.
• Scavengers ( melantho snails)  feed on algae on the sides of the pond and pots, but  do not clear green water. They overwinter in the pond. Their eggs can often be found on the underside of lily leaves during the summer.
• Fish – Will readily eat plants, mosquito larvae and other insects in the water, but may also be fed pelleted fish food. Goldfish, comets, faintails, shubunkins, orandas, moors and koi are all hardy and readily available in our area .
  • Do not overstock your fish !  The recommended rate is a maximum of 1” of goldfish or ½ “ koi per square foot of surface area to allow for growth and reproduction. Overstocking results in poor water quality and stressed fish which are more prone to disease and death. A large fish population, especially KOI, may require extra ( mechanical) filtration. 
  •  Do not feed fish at water temperatures  at or below  10⁰C.  Fish eat less as their metabolism slows down in cooler water ( spring /fall).

  Just like a regular garden, a water garden also has distinct seasons and growing periods. In the spring, plants slowly begin growing as both water temperatures and light increase. During this period the pond will experience an algae bloom and green water. In moderate amounts algae can have beneficial effects on water quality and create better conditions for your fish. A spring bloom is normal for even established ponds, although it will be less pronounced than in a new pond. Be patient; as your plants grow and provide cover, and your pond rebalances this will pass.  Now is the time to check your plants and fish and replace anything that may not have overwintered successfully. It is also the time to clean out any debris that may have collected over the fall and winter, split any plants that have overgrown and fertilize your lilies and other aquatic plants. If you have fish, this is when they resurface from the bottom, begin eating again and may spawn. With luck, frogs and toads will visit your pond to lay eggs. You may also have visits from neighborhood cats, raccoons, and a variety of birds, including herons, who will likely relish the treats you have cultivated for them! 

During the summer, the fish, frogs, insects  and plants will grow actively. Light and warmth is what is needed for successful blooming of hardy and tropical lilies, so placement of your water feature to maximize these elements is important. You can add many varieties of tropical plants to enhance your enjoyment, such as night blooming lilies and fragrant day lilies, to name but a few. Every pond should have a few water hyacinths to help purify the water, but beware, during ideal conditions they will multiply rapidly and need thinning on a regular basis to avoid overcrowding other plants. Sometimes plants will become infested with aphids. It is a simple matter to spray the plants with a hose to remove them, and then the fish will eat them.  During warm weather or hot spells it is common for oxygen deficiencies to occur in the pond, putting your fish in danger. At this time, fish need more oxygen than in the winter and spring, and the warm water holds less oxygen. If you see your fish gasping at the surface of the pond, this indicates insufficient oxygen in the water. In order to maintain high enough oxygen levels adding some type of water movement, like a fountain, spitter, or waterfall is helpful, especially if you have a large fish population.

Another common problem is algae. It is beneficial to have some algae in the pond as the fish and snails will readily use it as food. The moss and slime found on rocks and around the edges of the pond are good forms of algae as they act as filters to improve water quality as well as providing food for fish, so there is usually no need to remove it. Indeed, some people do not feed their fish at all, preferring to have them rely on what is supplied within the pond’s ecosystem, be it plant or animal life. The most common problem is string algae or blanketweed. A large amount of algae will contribute to low oxygen levels and needs to be removed and controlled. By providing 75% surface coverage, for example lily leaves, and sufficient oxygenators and floating plants, such as water hyacinths, to compete for nutrients and starve the algae this can be controlled naturally.   Removing excess algae by hand and placing bags of peat or barley straw in the pond, to temporarily change the pH of the water creating undesirable conditions for algae growth, are  other routine solutions to this problem.