Water Garden Plants: How to Maintain a Water Garden

A water garden is a type of garden built around a water feature, incorporating water-thriving plants that emerge out of the water, float on the water surface, or grow entirely submerged. A water garden can be as large as a backyard pond (if you have adequate yard space) or as small as a bowl of water (popular with apartments and renters).

There are a wide variety of plants that will grow well in water gardens, including:

1. 1. Outdoor shallow water plants: Many plants grow well with “submerged feet,” or with their roots in water or waterlogged soil and leaves exposed to the air. Also called bog plants, wetland plants, or marginal plants, these types make great additions to the edges of outdoor ponds, growing out of the top of aquariums, or in water vases or container water gardens in your home.
2. 2. Cold-hardy plants: There are many cold-hardy shallow plants that you can grow in your water garden. Popular options include arrowhead plants, water irises, cattails (Typha spp.), water celery, pickerel rush, sweet flag, and water mint. Shallow tropical plants include taro (colocasia), cannas, ludwigia, horsetail, and pitcher plants.
3. 3. Shallow water houseplants: Many common houseplants and indoor plants will grow roots in freshwater from propagation through maturity, including lucky bamboo, begonias, pothos plants, philodendrons, alocasias, orchids, peace lilies, and monsteras. Learn how to build an indoor water garden with this complete guide.
4. 4. Deepwater plants: Deepwater plants root their rhizomes in the soil at the bottom of ponds and grow long stems until their green leaves and flowers reach the surface. These plants can provide beauty and visual interest in the center of a pond, and dwarf varieties can be great additions to smaller water gardens. Common deepwater ornamentals include hardy water lilies (Nymphaea Spp.), tropical water lilies, lily pads, water lotus flowers (part of the Nelumbo genus), and water hawthorn.
5. 5. Floating plants: True floating plants exist only on the water’s surface, growing dangling roots that draw nutrients from the water column. Floating plants add a marshy, natural look to a water garden—common options include duckweed, frogbit, Azolla, water lettuce, and water hyacinth.
6. 6. Fully submerged plants: While most water garden plants like to grow immersed or partially out of the water to have unlimited access to carbon dioxide, some varieties will happily grow entirely submerged in water. Common submerged plants (also called oxygenating plants or aquatic ground covers) for small ponds include pennywort, hornwort, water wisteria, and tape grass. Small plants—like dwarf Sagittaria, java fern, java moss, Anubias, and Cryptocoryne—will stand out for smaller water gardens or home aquariums.

Water gardens require slightly different care than traditional gardens:

• Balance the nutrient levels: Nutrient balance is the key to a healthy and beautiful water garden—inadequate nutrients will likely lead to algae growth as your plants struggle to compete. Pay attention to your selection of aquatic plants, noting whether they feed primarily through their roots or mostly through the water column. Choose a balanced aquatic fertilizer that you can apply either in the soil or directly to the water.
• Trim plants regularly: Regularly prune your garden pond plants to remove yellowing or dying leaves that attract algae or pests. In addition, trimming stem plants encourages them to grow back bushier and denser, giving your water garden an even lusher look.
• Top off the water: In most cases, the water from a water garden will slowly evaporate into the atmosphere, reducing the water levels and leading to an unkempt look, exposed plants, or hard-water lines. To avoid this, regularly top off the water in your garden to keep the display looking fresh and vibrant.
• Add water agitation: Still water can cause problems in water gardens—it may develop a film over the top, fail to circulate nutrients properly, or become a target for breeding mosquitoes or other pests. Consider adding a small amount of water agitation (like a pump, water fountain, or waterfall) to keep your pond water circulating.
• Prep for aquatic animals: Some home gardeners add koi fish, snails, or shrimp to their water gardens. These aquatic animals can be a great part of the ecosystem, helping keep plants clean and offering natural fertilizer in the form of waste. Before adding aquatic animals to your garden, treat your water with a conditioner to remove chlorine that may come from the tap.
• Understand the nitrogen cycle: Read up on the nitrogen cycle—a process of adding ammonia to the water over several weeks—to build up your water garden’s healthy bacteria and make the system sustainable for animal life.
• Prepare for winter: After the growing season, if your water garden is outside and you live in a colder climate, you may need to winterize it to help it survive the cold winter months. In general, clear off debris, remove annuals or tender tuberous plants, and trim hardy perennial plants down to the ground, leaving their roots underground to sprout new foliage in the spring.

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