A Container Water Garden: Sooo Easy!

You’ve been dreaming of a water garden, but can’t find a place in your budget for such a massive installation? Or you just don’t have the space? Well, here’s a water garden that won’t cost and arm and a leg; plus it takes up almost no space: a container water garden. A “pond in a pot”, so to speak.

It can fit in anywhere, even on a balcony or terrace. In fact, even on a table! And all you need is a container without a drainage hole, a few pots of aquatic and shallow-water plants and some floating plants. The final but invisible touch is to add one or two submerged aquatic plants, also called oxygenating plants. Their role is to filter the water and keep it clear.

The only maintenance for a container water garden is to add water when the level drops and perhaps to slip a few water-lily fertilizer tablets into the plant’s pots. You don’t even need a pump! There is probably no garden easier to maintain than a container water garden!

Any size container is suitable, from a kitchen casserole to a half barrel. Still, a larger container means you can add more plants and increases the design potential. Water depth too is of little importance: you can use a deep container or a shallow one, as long as it is deep enough so you don’t see the pots you place in it.

As long as water is about 40% covered in vegetation (floating plants multiply at an incredible rate, so you’ll reach 40% in no time) and there are submerged plants in the container, there’ll be no algae and the water will stay clear. 

Do not put fish in your container garden, however: they dirty the water with their excretions and they will stimulate algae growth. Besides, container water gardens aren’t very fish-friendly, as the water heats up considerably, causing the fish to suffer.

You’ll discover that flowering aquatic plants, including the water hyacinth (Eichhornia crassipes), bloom much profusely in a container water garden than in an in-ground pond. That’s because the water in a container warms up much more than pond water and warm water stimulates bloom.

Choice of Plants

There is a huge selection of plants for a potted garden. Here are some examples:

Floating Plants

1. Fairy moss (Azolla caroliniana)
2. Salvinia (Salvinia spp.)
3. Tropical water lily* (dwarf) (Nymphaea spp.)
4. Water hyacinth (Eichhornia crassipes)
5. Water lettuce (Pistia stratiotes)

*The water lily is not really a floating plant, because it grows from a pot placed at the bottom of the container, but the leaves float on the surface of the water.

Submerged Plants

A reminder: you will likely not see submerged plants, or just barely, because they are out of sight at the bottom of the container, but their presence is still vital to the balance of your water garden.

1. Anacharis (Egeria densa)
2. Fanwort (Cabomba caroliniana)
3. Elodea (Elodea canadensis)
4. Hornwort (Ceratophyllum demersum)

Shallow-Water Plants

1. Canna (Canna cvs)
2. Corkscrew rush (Juncus effusus ‘Spiralis’)
3. Dwarf cattail (Typha minima)
4. Lotus (dwarf varieties) (Nelumbo cvs)
5. Papyrus (dwarf varieties) (Cyperus papyrus)
6. Pickerel rush (Pontederia cordata)
7. Taro (Colocasia esculenta)
8. Umbrella palm (Cyperus alternifolius)
9. Variegated sweet flag (Acorus calamus ‘Variegatus’)

If the container is very deep, raise the pots of shallow-water plants on bricks or inverted pots. Their root ball should be covered by no more than 2 inches (5 cm) of water.

Winter Care

In mild climates, a container water garden can survive from one year to another with no special care. Growth and flowering will likely stop in the winter, but then will resume with the return of warmer weather in the spring.

The story is very different in colder climates. Most of the aquatic plants you’d want to grow in a container water garden are of tropical origin and will not survive winter outdoors where temperatures drop to freezing. Nor are most of them easy to keep indoors over the winter. Floating plants, especially, need 12 hours a day of intense sun to do well, not easy to replicate indoors during the short days of winter. So, it’s usually best to consider container water garden plants as annuals and to buy new ones each year. I’m not saying not to try and keep them going (that’s your choice). Just don’t be too disappointed if they don’t survive.

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So, what are you waiting for? When nights warm up in late spring, it’s time to start your container water garden. Just dig around in your attic for a suitable container and head off to your local garden center or water garden nursery for a few plants: you can have your water garden up and running in less than an hour!