Water features set the tone of any garden – large or small, no matter what the theme. And when it comes to aquatic plants, your garden is open to all kinds of possibilities. Water lilies, irises, cattails and more – these are just some of the plants that might float to mind when contemplating a water garden. Aquatics growing in and around water features help soften the hard edges of man-made structures, blend water features into the surrounding landscape, filter the water and provide cover for fish.
Water features can be big or small. Here, an old stump was hollowed and lined to create a planting basin in a woodland garden.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Tropical plants like broadleaf philodendron and amaryllis are well-suited for planting near water features.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
There are four basic categories of aquatic plants: Shoreline plants grow in the moist soil around the edges of the water, marginals and deep-water submersible plants grow in soil in the water, and floaters grow atop or underneath the water.
Shoreline plants should be placed in the ground outside the liner of a water feature as you would other garden plants. Marginals and deep-water submersible plants are the most “offbeat” aquatics to plant because they need to be potted in a suitable growing medium within a specialized container (a shallow plastic basket or porous terra-cotta pot). Once potted, the container can be placed in the water at the specific depth required for the plant. Generally, shallow-depth marginals grow in water less than 6 inches deep. Deep-depth marginals grow in water 6-12 inches deep, and deep-water submersibles grow in water deeper than 12 inches. Use underwater risers (like a brick, flat rock or pond shelf) in the bottom of your aquatic feature to adjust the depth of each basket. (Follow the photos and captions at the end of this article to learn the proper steps to planting submerged aquatics in containers.)
Surface floaters grow unanchored by floating on the top of the water, while submerged oxygenators grow below the surface. You can just place these plants in the water to grow, tethering them with monofilament line to hold their position if you’d like. Many floating plants have a tendency to spread and require frequent thinning. A few, like water hyacinth, have even attained weed-like nuisance status, so do be careful when choosing your aquatic plants. (Most aggressive plants are prohibited from being sold, but still carefully read all plant tags and check with the Learn2Grow Plant Database or your local garden center if you have any questions or concerns about a particular species.)
To get your water garden plants off to a swimmingly good start, it’s important you plant them right.
Aquatic Plant Planting
Aquatic Plant Planting - Step 1
Choose an appropriate aquatic planting container and growing medium suited to your particular plant.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Aquatic Plant Planting - Step 2
Line the container with landscaping filter fabric, weight the base of the container with dense stone, then fill the planter with soil mix, leaving space for the eventual plant root ball and a 1-2 inch layer of pea gravel (to be added once the plant has been planted). Soak the container for 24 hours in a bucket of water or a filled water basin to exhaust air trapped in the soil and to saturate the organic elements.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Aquatic Plant Planting - Step 3
Remove the thoroughly soaked container and its soil from the water basin. Gently mix the soil to incorporate any waterlogged organics that have settled on the soil surface.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Aquatic Plant Planting - Step 4
Open a hole in the soil for the roots of the plant, removing some soil if necessary. Remove the plant from its nursery pot, spread the roots and gently transplant the species into the soil as you would any other plant. Gently pack the soil around the roots, adding more as needed. Immerse the container in another water bath for a few minutes until bubbling stops, then remove and drain it. Fill all voids and replace any soil that has settled.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Aquatic Plant Planting - Step 5
Cover the growing medium to the rim of the container with rinsed pea gravel. (This protects the plant’s roots and surrounding soil from erosion, as well as further weights the container to prevent movement.)
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Aquatic Plant Planting - Step 6
Carefully position the container at the required depth in your water feature. Stabilize and secure the container, using cobblestone or other stones from your water feature if necessary. (Once the pot is fully saturated, it’ll be less likely to float or be tipsy.)
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
Aquatic Plant Planting - Step 7
Place immature aquatic plants on adjustable stands, with their foliage just below the water. As the plants grow and leaves reach the water’s surface, progressively lower the stand until it’s at the appropriate depth for your submerged aquatic.
Photo Credit: ©2001 Dolezal Publishing/John M. Rickard
