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Aquatic Plant Gardens: Home

Nelumbo lutea (American yellow lotus) in conservatory pond at NYBG
Nelumbo lutea (American yellow lotus) in NYBG Conservatory Pool

Water gardening is one of the easiest and most practical ways of transforming your garden, or any outdoor space, into a cooling retreat with lush and varied plants. This guide is designed to inspire and inform the beginning water gardener with ideas on getting started as well as on maintaining a beautiful and ecologically balanced water garden of any size.

There are three types of pond to consider:

  • Flexible Rubber Liners: Pond Guard 45 mm by Firestone lasts twenty years. Xavan Liners by Tetra last twenty-five years. Lay out the desired shape with rope or hose. Excavate hole 18 to 36 inches deep. Leave a shelf  6 to 12 inches below water surface around pond edge for marginal plants. Add several inches of sand. Make sure that the top of the pond is level. Drape your liner over excavation, leaving overlap around the edges. Place rocks over edges and add water.
  • Pre-formed Fiberglass Ponds: These can be placed above ground or installed. Excavate an area six inches wider and three inches deeper than the pond form. Place three inches of sand in the bottom of the hole. Lower the pond into your hole and check that it is level. Add water slowly while re-checking level and add soil to the gaps around pond. The lip of the pool may be concealed with paving stones or plants.
  • Container or Water Tub Garden: Any clean, water-tight container that holds at least 4 gallons of water may be used. Possibilities include whiskey barrels or casks, old sinks or tubs, ceramic bowls, wash tubs and horse troughs. 
Ceratophyllum demersum drawing courtesy of Biodiversity Heritage Library
Hornwort (Ceratophyllum demersum) is a submerged plant (1837 drawing ;courtesy of Biodiversity Heritage Library)


It is best to site a pool in a location that is as level as possible to avoid the damaging effects of both surface run-off and ground water. Keep the pool away from overhanging trees to avoid root damage during construction and falling leaves thereafter. Low lying areas may be more suitable for locating natural ponds.

Water Plants

Cattail plants photo courtesy of Flickr cc/ Jeffrey Kotur
Cattails are marginal plants (photo courtesy of Flickr cc/Jeffrey Kotur)

Not all aquatic plants are alike. Different plants have different requirements and each type serves a unique purpose in your pond or pool ecosystem. Here is a simplified list to help you create a stunning water garden.

  • Deep Water Aquatics grow on the floor of the pool and produce leaves that float on the water surface (e.g. water lilies). Despite the name, many deep water aquatics prefer not to have more than 18 inches of water covering their root system. They provide surface cover thus preventing oxygen loss and evaporation.
  • Marginal Plants grow in the water at the edge of the pool (e.g. cattails, irises). They are tolerant of standing water and wet conditions all year round. They provide refuge for wildlife, especially aquatic insects and they provide vertical interest in the garden. Acorus calmus (sweetflag), Iris pseudacorus (yellow flag), Typha minima (cattail), Pontederia (pickerel weed) and Schoenoplectus lacustris (bullrush) are all good choices.
  • Bog Plants require very damp soil, but will not tolerate standing water, especially in the winter (e.g. papyrus). They consume excess pond nitrogen and phosphates.
  • Floating Plants float around freely on the surface of the water (e.g. duckweed, water lettuce). They derive their nourishment from the water. They provide shade and have a role in oxygenation. Azolla filliculoides (fairy moss) is a floater.
  • Submerged Plants, also called oxygenating grasses, grow completely beneath the water although they may produce flowers on the surface of the water (e.g. elodia). They produce oxygen through photosynthesis and absorb carbon dioxide. Plants such as Myriophyllum aquaticum (parrot's feather) and Ceratophyllum demersum (hornwort) work well in a contained water garden though many of the submerged species are invasive in our area's open waters.
The floating plant Azolla caroliniana at NYBG; photo by Marlon Co
The floating plant Azolla caroliniana at NYBG; photo by Marlon Co


  • Test water regularly to ensure that pH is kept between 6 and 7
  • Fix leaks promptly with a pool repair kit
  • Pumping may be required as sediment builds from year to year. Organic debris like grass and leaves needs to be removed promptly
  • Regularly lift, divide and prune plants to prevent overgrowth during spring and summer months
  • More rampant species can be managed by planting in submerged containers and thinning occasionally
  • Maintain a regular fertilizing schedule
  • While mossy algae is beneficial at the pond's edge, keep other algae in check 


Let water lilies die back in pools if they are submerged under 24 to 48 inches of water. Drain small water lilies in containers and store them in a cool, frost-free location until the following spring. If a pump is used remove it, clean and store it until the spring

To allow for escaping gases from the decomposition of organic matter, place a pan of boiling water on the ice. This will create an area of aerated, ice-free water.

Concrete is vulnerable to cracking. Float a piece of wood or a rubber ball on the surface of a concrete pool to absorb the pressure of the ice.

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