Happy Spring! Our tumultuous winter is being whisked away by a strong promise of pleasant weather and the anticipation of a tranquil water gardening season.
Opening our ponds for the season presents an opportunity to not only use tried and proven plants but also add some unusual, often overlooked species. Plant selection depends upon the design of your pond and a planting plan. Choose plants that will look aesthetically pleasing and also assist in achieving a balanced ecosystem.
The four categories of pond plants are:
Submerged plants that can live entirely underwater. These plants are often called oxygenators but this is somewhat of a misnomer. They produce oxygen during the daylight hours but consume oxygen during the night. They serve an important role in pond water quality by filtering excess nutrients and providing shelter for fish. Some submerged plants such as Vallisneria are rooted in the substrate and send elegant foliage up to just under the water’s surface. Other submerged plants such as Ceratophyllum, are not rooted and freely float under the water’s surface.
Vallisneria at left. Photo by Stephen G. Noble
1. Vallisneria americana (tape or eelgrass) must be rooted in a pot filled with a mixture of sand and soil. Place planter in water .5 to 1 meter deep. Vallisneria looks best at the base of a waterfall where the current sends the floating foliage out into the water garden. Propagation is via runners and seed pods.
2. Ceratophyllum (Hornwort) has an emerald green dense foliage. Extreme cold tolerance makes Ceratophyllum and ideal plant for early spring and late season use. The plant can easily grow to more than three meters in length over a growing season. Do not root Ceratophyllum since it receives nutrition from the water. It is a free-floating plant. Propagation involves nothing more than clipping off a 10 centimeter piece and sharing it with another water garden keeper.
Utricularia gibba. Photo by Stephen G. Noble
3. Utricularia spp. (Bladderwort) are the carnivores of the plant world. These highly unusual plants are ideal for small water and container gardens. They gain nutrition by trapping small organisms in bladder-like traps. Utricularia need a well-established pond with plenty of daphnia, nematode and mosquito larvae to thrive. Propagation is by clippings or seeds.
Rooted floating plants such as the all-time favorite, Nymphaea spp. (waterlilies, pond lily), grow with their roots and petioles submerged and their leaves floating on the water’s surface. Waterlilies are categorized into two groups: hardy and tropical. Hardy lilies are capable of withstanding severe winters while tropical lilies must be brought indoors.
Hardy Waterlily Nymphaea odorata ssp odorata. Photo by Stephen G. Noble
4. Nymphaea ‘odorata‘ produces a dainty white bloom. Place the rhizome in a pot, two-thirds filled with potting soil. It spreads to about one-meter wide and should be planted one meter deep. Propagate this plant by dividing the rhizome.
Nymphaea firefox. Photo by Stephen G. Noble
5. Nymphaea ‘Firefox’ is a spectacular, daylight blooming, tropical waterlily. Wait until the water temperature is consistently above 21 Centigrade before introducing tropical lilies to your pond. Colder water will retard growth. Place the pot in one meter deep but this plant is also ideal for water as shallow as .5 meters. Propagate tropical lilies by removing side shoots from the main tuber.
Nymphoides aquatica. Photo by Stephen G. Noble
6. Nymphoides aquatica is known as the banana plant because of its unique clustering tubercles that look surprisingly like a bunch of un-ripened bananas. The ‘bananas’ are actually plant food reserve organs. Nymphoides aquatica is normally sold as an aquarium plant but is magnificent in smaller ponds and shallow areas of watergardens. Nymphoides aquatica produces a number of cup-shaped, rounded leaves that are notched at the base giving the leaf a somewhat heart-shaped appearance. Most of the leaves float on the surface but a few remain submerged. The leaves are predominately green on top with ill-defined, yellow highlights. The undersides of the leaves are purplish colored, highlighted by white veins and have a rough, pebble appearance. The leaves grow to about two-inches in diameter and look like small lily pads. Propagation is by runners or division of the rootstock.
True floating plants are free floating and not rooted in any substrate.
7. Eichhornia crassipes (Water hyacinth) is a watergarden mainstay. Fast growing, this easily propagated plant is an outstanding component for maintaining excellent water quality. This plant produces a gorgeous lavender flower. Reproduction is primarily by runners which form daughter plants. Give extra plants to other pond keepers or use them as compost. This highly invasive plant must never be released into waterways.
Pistia stratiotes. Photo by Stephen G. Noble
8. Pistia stratiotes (Water lettuce) looks sort of like a head of lettuce foating on the water. It deserves a place in the watergarden due to its rapid growth, pleasant appearance and tremendous ability to remove contaminants from the water. A fully grown plant can reach 60 centimeters in diameter. It produces offshoots that grow from the base of the mother plant. Reproduction is very rapid. Like Eichhornia crassipes, it too must never be released into waterways.
Eichhornia crassipes. Photo by Stephen G. Noble
Marginal plants grow at the pond’s edge. Some require their roots to be completely submerged while other marginal plants prefer only wet soil. No pond or watergarden is complete without marginal plants. These plantssoften the transition from yard to pond. Furthermore, they invite birds, bees and butterflies.
Cyperus alternifolius. Photo by Stephen G. Noble
9. Cyperus alternifolius (Umbrella grass) is one of the most versatile marginal plants. This always-green tropical plant is happiest when rooted in potting soil and placed in 2 to 20 centimeters of water. It grows over two meters tall and makes a striking focal point. Propagate by dividing the root mass or by bending a stem to partially submerge the leaf until roots appear.
10. Lobelia cardinalis (Cardinal flower) has crimson flowers that are butterfly and hummingbird magnets. It requires very moist soil or a water depth up to 8 centimeters. The stems grow to a height of one meter and the plant spreads to 30 centimeters in diameter. Propagate the same as Cyperus alternifolius.
Please be responsible and check local and federal laws prior to obtaining plants for your water feature.
Enjoy your watergarden!