How To Treat Hard Water In The Garden

Water Garden Care Guide

Water gardens are a unique and interesting addition to any garden. These tips ensure the water garden plants in your landscape stay healthy and beautiful.

Water garden care starts with good assembly. Add a fountain pump, water, and your choice of pond plants to the water compartment. Weigh the pots down with rocks if needed (taller plants tend to be top-heavy in a breeze). Fill the garden compartment with potting mix and your choice of plants. Use easygoing plants like pentas, gomphrena, and licorice plant. After finalizing the water garden design, the rest of the work is upkeep and maintenance.

Some water garden plants grow in containers submerged beneath the surface of the water. Others float directly on the surface. Yet others grow in moist soil around the edge of the pond. A well-designed water garden uses a combination of these types of plants.

water plants by pond

Pond Edge Plants

Plant varieties that have roots that grow in wet soil directly—such as sweet flag, marsh marigold, lobelia, rush, pickerelweed, and cattail—in the ground at the edge of a clay-lined pond. If your water garden has a plastic liner, pot the plants in plastic nursery containers and place them in the pond with just the base of the container submerged.

Water Lilies and Submerged Plants

Water lilies and lotuses are the jewels of the water garden, thanks to their spectacular colorful blooms. Grow them in submerged containers. Place the water lily container so that it is submerged 6 to 36 inches below the water level. Permeable mesh pots or containers made of landscape fabric are often used for planting water lilies, although plastic pots work well, too. Avoid using regular potting soil—it will float out of the container. Instead, use a good water garden potting mix. Lotus needs a large container because its rhizomes spread rapidly.

adding water plants to water container garden

Floating Plant Types

Floating plants are the ultimate in easy-care gardening. There's no potting necessary—just set them in the water, and they'll float on the surface. In warm-winter climates, some floating plants can become invasive, so check local regulations about which varieties you can grow. Water lettuce and duckweed are common picks for water gardens.

Pond Location

Place the pond where you can enjoy the sight and sound—a deck or patio is a good choice. The location should be close to a power outlet for convenience (you can position plants strategically to hide the power cord). Run the fountain regularly to prevent stagnant water that invites mosquito breeding. Or use mosquito-repellent dunks.

dividing Japanese irises plants on table

Credit: Perennials SIP: Ensata Garden - Dividing Japanese Iris

Water Garden Care

Remove spent flowers, yellowing foliage, and excess plant growth. If floating plants multiply to cover more than 60 percent of the pond's surface, pull out and compost the excess foliage. Divide overgrown water lilies and other aquatic plants early in the season.

In autumn, you may wish to cover the water garden with netting to prevent leaves from collecting in the pond. If leaves do blow into the water, remove them to prevent them from tying up oxygen as they decompose.

Algae buildup can become a problem in water gardens. Barley straw or pellets placed in a pond or stream in spring prevents algae growth. A good filter or clarifier also prevents the development of algae. Use a fountain or waterfall to keep the water aerated and ward-off foul-smelling bacteria.

Watering aquatic plants couldn't be easier. Simply maintain the pond level at the correct depth so plants at the water's edge don't dry out and so that roots of submerged plants remain covered. Refill your water feature before the water level drops several inches. Automate the process by installing a float valve that automatically turns on the water when the level drops to a set point and shuts off when full.

Floating plants derive their nutrition directly from the water. Water lilies and other containerized plants, however, often need fertilization to grow and bloom well. Several types of commercial water garden fertilizer pellets are available. Place these directly into the potting soil of container plants.

Watering Plants

fertilizer tab in lily plant pot

Water Plants Fertilizer

Water Plants in Winter

If you live in a cold climate, empty the container in fall and store it and the pump under cover for the winter. Most of these plants can be overwintered outdoors in moist soil in Zones 5 or higher. Exceptions: Umbrella palm and water lettuce will not survive freezing, so place them in a tub of water in a cool basement near a window where they can go dormant. Air-dry canna tubers and store them in peat moss or sawdust in a cool but not freezing location.