Plant a Pond
There are four ponds on the balcony – water gardens are easy to set up.
If you are setting up ponds that include fish, add oxygenator plants like Hornwort and let the water gas off for at least 48 hours before adding fish. Hornwort, Ceratophyllum demersum is a hardy rootless pond plant that floats freely in a container water garden. It oxygenates the water, grows quickly, loves the sun, provides hiding places and shade for fish and is a rich dark green colour.
Want fish. Pond comets grow quickly and are easy to keep. Comets are single-tailed goldfish and are the most hardy of all pond fish. They thrive in cold water and depending on the number of fish and the size of the container, you don’t necessarily need a filter and pump to oxygenate the pond. Comets don’t eat the Hornwort but will nibble on other floating plants. I find there is always a jumper in the group and I don’t winter over the comets.
Container water gardens should have at least six hours of direct sun a day – essential if you are trying to get a water lily to bloom. You’ll also need to top up the pond each week due to evaporation.
Water Pennywort, pictured left below, Hydrocotyle ranunculoides, Zone 5, has glossy green leaves that are round with scalloped edges. Plant stems are attached to the centre of the leaf and flowers are white to greenish-white with tiny, simple, five petal flowers.
This plant grows quickly, can handle the wind and leans to find the sun so place this plant in full sun. This is a marginal water plant with submerged roots and leaves and flower stalks that bend toward the water surface.
In Canada. Pennywort is found in Nova Scotia and British Columbia but my two plants came most likely from California. Water pennywort is included on British Columbia’s rare plant monitor list.
Parrot’s Feather, Myriophyllum aquaticum, Zone 6 is pictured below right. It is a submerged water plant. Set in the pond with at least 3 inches of water over the crown of the plant. Parrot Feather has red stems and feathery, delicate leaves that float on top of the water. It doesn’t like cool weather so don’t put it out too early in Zone 3.
Some of the water plants we get in Canada are invasive somewhere in the world – Parrot Feather is currently invading rivers, lakes and dams throughout South Africa.
Floating plants in the balcony garden ponds include Water Ferns, below left, Water Clover, Marsilea Mutica, below right and duckweed. Duckweed, Lemna minor, Zone 5 has tiny leaves and microscopic flowers.
Other floating plants I’ve successfully grown on the balcony include Water Lettuce, Pistia stratiotes, Zone 9. This pond plant has a grey-green leaf with a soft, velvet surface. It grows quickly and happily in Zone 3 and has interesting thick wrinkly leaves. Water lettuce tolerates more shade than many aquatic plants and fish like to hide in its feathery roots.
Frog Bit (Hydrocharis morsusranae, Zone 7) and Water Hyacinths below pictured left are other favourite floaters. Frog Bit has small shiny green clumps of leaves and very tiny white flowers. Fish like to eat the roots of this one.
So, if you choose plants that match your growing conditions, it’s easy. Want to try it?
Your container should be at least 15-20″ deep and 18-24″ wide and hold at least 5 gallons of water. A dark coloured container (inside) helps disguise the build up of algae and may help to warm the water and give the illusion of depth. No matter what container you choose, position and level it before you fill it – they are heavy and awkward to move around.
Your growing conditions are ideally 6 hours of sunlight per day.
Your pond water should sit for a couple of days before you plant or add fish to allow the chemicals in your local water ‘gas off’ and come up to ambient temperature.
Your plants get added next. Submerged plants in their containers go in first. Use bricks to set the correct depth for each plant in the container and add gravel to the top of the plants to keep the soil in place. Or better yet – many gardeners grow their pond plants in clean pea gravel because water plants get their nutrients from the water, not soil. Gravel planting helps keep a pond clean by removing soil contamination and gravel doesn’t compact down so this may give roots more oxygen. Floating plants go in last and if they cover more than half of your water surface they will help discourage algae.
- Cattails (6” under water”) and iris (2” under water) remove nutrients and filter the water, red stemmed parrot’s feather is an oxygenator and hornwort is a super oxygenator
- Tropical plants, including papyrus (2” under water), water lettuce (floater) and water hyacinth (floater) go out only when the weather is warm
- Water lilies are heavy feeders and need lots of sun.
Do you need a pump and air stone? If you can set up your pond near an outlet, add a simple pump and air stone to help oxygenate the water and add sound. But it’s not essential. I can get away without one because my ponds are relatively small and only sometimes feature fish. Because it is so dry here, my ponds also require fresh water to be added every week due to evaporation. So I have a constant flow of fresh water being added to the water’s chemistry every week. And to avoid mosquitoes using my ponds as a nursery, I ‘fluff’ the water surface or overfill the ponds when I top them up – avoiding standing water.
Balcony garden pond? Why not?