Beginner’s Guide to Creating Your Own Water Garden

Nothing creates a soothing atmosphere or adds life and movement to a home landscape quite like a water garden. In this blog, the home gardening experts share inspiration, ideas, and guidance for novice waterscapers. Waterscaping encompasses the design, installation, and maintenance of ponds and other water features. Installing a small pond or water feature in a home garden requires initial planning and continued maintenance, but overall is an achievable goal for gardeners looking to expand their plant palettes. As an added bonus, waterscaping can also attract more wildlife to your backyard. St. Louis Resources for large-scale Waterscaping Please note, this blog covers the very basics of small-scale, backyard waterscaping. If you want to learn more, we highly recommend seeking expert advice and resources from the Gateway Koi & Pond Club and the Saint Louis Water Garden Society. For larger pond builds or renovations, the Missouri Department of Conservation has resources for landowners with farm ponds or fishing ponds 0.25 acre or greater in size. 1. Decide what kind of water garden you want Before grabbing the shovel or renting an excavator, it is important to make a few key decisions about the pond. Do you want a naturalistic pond to attract more wildlife to your yard, such as frogs, turtles, and dragonflies? Or do you want a more formal water feature? Do you want to take care of fish in your pond? These factors will influence the size and depth of your waterscaping project. Once you have decided the key features and functions of your pond, you can start the building process. 2. Choose a location for your water garden Choose a location in a relatively flat area and mark out the shape for the pond. Consider how close the pond will be to electrical outlets, a water source, and potential viewing locations such as a patio or pathway. For maximum plant growth, the pond should be in full sun, but—be warned—this will also encourage algae. Partial shade will reduce algae growth, but likewise limit the potential of showy aquatic plants like waterlilies and cannas. Also keep in mind that placing the pond near deciduous trees will mean more time spent cleaning leaves out of the pond in the fall. 3. Create The Pond for Your Water Garden Once the pond is dug, make sure it is flat using a level and line the top with rocks. Although ponds can be built without synthetic liners, we recommend beginner pond owners use either flexible or pre-formed liners. These are relatively affordable and can be used in any soil type. Pre-formed liners are thicker and less likely to leak, but flexible liners give much more creative freedom when it comes to pond shape and size. If using a flexible liner, fill the pond slowly and then trim the excess. Rainwater is ideal for filling a pond, but tap water is also suitable as long as the chlorine can dissipate for 24 hrs or a water conditioner is used before adding plants and fish. Check the water level during hot summer weather and top it off as needed. 4. Add Pumps or Filters for movement and maintenance Pumps and filters are not strictly required for a healthy pond, but they oxygenate the water, create movement, and improve water clarity. All of these benefit the aquatic plant and animal life and increase your enjoyment of the pond. 5. Select the Plants for your water garden Now that the pond is built and filled, it’s time to add plants. There are three main types of plants used in backyard ponds: emergent plants, floating plants, and submerged plants. Emergent plants Emergent plants grow at various depths, with their roots and crowns underwater and foliage above water or floating. Both tropical and hardy water lilies are extremely popular emergent plants that grow well in 1-2 feet of water. Smaller, dwarf varieties will do best in 6-10 inches of water. They come in a wide variety of colors, including blue, purple, pink, yellow, and white, can be quite fragrant, and will produce a showy display of blooms during the summer. Aquatic cannas are usually hybrids of Canna glauca, an aquatic species from South America, and a terrestrial species. These cannas will grow well in water up to around 6 inches Pickerel weed (Pontederia cordata) This Missouri native emergent plant produces 2-to-4-feet tall clumps of glossy, arrowhead-shaped leaves and spikes of bluish-purple flowers in the summer. It has rhizomatous roots and can be planted in containers to help keep unwanted spread in check. deep. Its flowers come in warm shades including yellow, pink, red, and orange. Green arrow arum (Peltandra virginica) Another emergent plant native to Missouri, the green arrow arum is quite shade-tolerant and is a good choice for ponds that are not in full sun. It will grow well in water up to 6 inches deep. Floating plants Floating plants will move freely over the surface of the pond, their roots suspended in the water below clumps of leaves. Mosaic plant (Ludwigia sedoides) A striking floating plant with diamond-shaped leaves that radiate outward and turn red with age. It is not cold-hardy and is grown as an annual in water gardens and ponds in St. Louis. Water lettuce (Pistia stratiotes) The velvety leaves and vigorous growth habit of this frost-tender floating plant make it another popular choice for St. Louis area waterscapes. American frogbit, sponge plant (Limnobium spongia) This native floating plant is popular for use in both aquariums and backyard ponds. The green heart-shaped leaves are a favorite food of turtles. Submerged Plants Submerged plants grow completely underwater and can help to oxygenate the pond while competing with algae. American eelgrass, wild celery (Vallisneria americana) The graceful, ribbon-like leaves of this native submerged plant are a favorite food of ducks and other waterfowl. Female plants form unique, spiraling flower stalks with a single, small, creamy-white flower suspended at the water’s surface. Canadian pondweed (Elodea canadensis) Although considered too aggressive for most fishing ponds, this native elodea can be grown in aquariums and backyard ponds. It prefers cooler water temperatures between 50-70°F but will tolerate temperatures in the low 80s. 6. Avoid Aggressive and Invasive Plants If you want your water garden to grow and thrive, we suggest avoiding these aggressive and invasive species. Chameleon plant, houttuynia, fish mint (Houttuynia cordata ‘Chameleon’) Do not be fooled by the colorful leaves and showy, white flowers of the chameleon plant. It spreads very aggressively by rhizomes and is extremely difficult to control. It is tolerant of wet soils and will grow as an emergent plant in up to 2 inches of water. Duckweeds (Lemna, Spirodella, and Wolffia) These tiny floating plants will quickly cover the entire surface of a pond and are extremely difficult to control once introduced. We recommend not purposefully adding them to a backyard pond. Giant elodea, Brazilian elodea, anacharis (Egeria densa) One popular—if not the most popular—submerged plant for use in aquariums and waterscapes. However, giant elodea is native to South America and has the potential to invade local Missouri waterways. Never dump unwanted aquatic plants into local streams and consider using the visually similar and native Elodea canadensis instead. Got plant questions? Ask the Garden’s Horticulture Answer Service Garden staff and Master Gardener volunteers provide personalized answers to your specific gardening questions over the phone or through email. - Phone: 314-577-5143 - E-mail: plantinformation@mobot.org Justine Kandra | Horticulturist with the Kemper Center for Home Gardening. Leave a Reply