By Carl Wilson, Horticulturist, Denver Cooperative Extension
Although many people are putting in full-scale pond features, you don't need to do that to enjoy water garden plants.
Container water gardens are as much alternatives as container flowers are to a full-size flower bed. The only difference is that you use pond plants in a water growing media as opposed to land plants in potting soil. Even a bowl can hold a small water plant. A nice size container is 12-to-24 inches wide by 12-to-16 inches deep. While you can seal ceramic containers or use liners in wooden barrels, plastic containers may be easiest to use. Just as with container flowers, group various-sized water garden containers to make a big splash. Depending on the size of the container, select a spiky, erect plant, such as sweet flag, Acorus calamus, or yellow flag iris, Iris pseudacorus. Combine with a broad-leaf plant, such as Giant arrowhead, Sagittaria latifolia, or calla lily, Zantedeschia aethiopica. Add a cascading plant, such as water mint, Mentha aquatica, or parrot feather, Myriophyllumaquaticum.
You will pot your plants in containers filled with a heavy, packed clay and submerge them underwater. Use bricks or an old, terracotta pot to prop them off the bottom so the foliage is above the waterline. Finish off the planting with some floating plants, such as water lettuce, Pistia stratiotes, or water hyacinth, Eichhornia crassipes. Don't crowd too many plants into a container. Two to three potted plants and some floaters will make quite an impact.
Locate the container where it will receive 6 hours of sun and top it off every few days as water evaporates. When plants begin to grow, add a fertilizer tablet available at the garden center where you purchased your plants. If algae develop, remove the water plants, empty the container, refill with clean water and replace the plants. Mosquitoes have not been a problem in container water gardens as the living plants keep the water from becoming stagnant. If they do develop, remove them by overfilling your container and letting the mosquito larvae run out with the water flowing over the top.
Container water gardens are really quite simple and worth a try.
How to assemble a container water garden
For more examples of container water gardening, see our Photo Gallery of Container Water Gardens.
For more information on water plants, see Selecting Plants for the Water Garden.
Photograph courtesy of Judy Sedbrook.
Diagram courtesy of Sherrie McGee.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010