Aquatic Plants Guide
Oxygenate, beautify, and balance your pond naturally
Why Aquatic Plants Matter
Aquatic plants are not just decoration — they are active participants in the pond ecosystem. They oxygenate the water, provide essential fish habitat, shade the water surface to keep it cooler and clearer, and directly compete with algae for the sunlight and nutrients that fuel blooms. Understanding the three plant categories — floating, submerged, and marginal — helps you build a pond that stays healthy with less intervention.
The Three Plant Categories
Floating plants
These plants float on the water surface. Their roots may or may not anchor to the bottom. Examples include Water Hyacinth, Water Lettuce, and Duckweed. Floating plants provide immediate surface coverage and shade, and are excellent at absorbing excess nutrients from the water.
Important: floating plants are tropical and must be removed from the pond before the first frost. They will not survive a Utah winter.
Submerged plants
These plants grow entirely underwater, with soft, flexible stems adapted to aquatic life. Examples include Water Lilies (which have surface leaves but submerged root systems), Water Hearts, and Hornwort. Submerged plants are generally winter-hardy perennials and can remain in the pond year-round.
Marginal plants
Marginals are found at the pond edges where the water depth is 1 foot or less. They include Aquatic Forget-Me-Not, Aquatic Iris, Bloody Dock, and Cattails. Marginals can be planted directly in pots or bare root, and many are winter-hardy perennials.
Why Plants Are Beneficial
- Shade the water surface, which cools the pond and reduces algae-favoring conditions
- Compete directly with algae for sunlight and dissolved nutrients (nitrogen, phosphorus)
- Give fish a place to hide from predators and reduce stress
- Provide spawning habitat for fish during breeding season
- Add aesthetic beauty and naturalize the water feature
- Marginal and bog plants also act as biological filters, trapping sediment and housing beneficial bacteria
How Many Plants Does Your Pond Need?
Covering 70% of the pond surface area is the target for effective algae control and meaningful fish shade. This sounds like a lot, but a combination of all three plant types — floating, submerged, and marginal — makes it achievable without overcrowding any single area.
Guidelines:
- Give submerged plants at least a 2–3 foot radius between pots to allow root spread
- Use floating plants to quickly fill open water areas
- Line the pond edges with marginals at 1 foot or less depth
A mix of plant types is more resilient than relying on a single category.
When to Add New Plants
Aquatic plants prefer milder temperatures to acclimate to a new environment. The best planting window is after Mother’s Day (mid-May) through September. July can be particularly difficult — the intense Utah heat stresses newly introduced plants before they can establish roots. If you must plant in July, add plants during the cooler morning hours and monitor closely in the first week.
Avoid adding new aquatic plants after October, as shortening days and cooling temperatures will interrupt establishment before winter.
Ongoing Plant Care
Fertilizing
Aquatic plants in pots are isolated from natural soil nutrients. Fertilize monthly during the active growing season (May–October) using aquatic plant fertilizer stakes pressed into the pot substrate. Do not use standard garden fertilizer — it will dissolve into the pond water and fuel algae growth.
Pruning
Remove dead, yellowing, or spent growth so that new growth receives adequate sunlight. Overgrown foliage shading younger stems will reduce overall plant health and flowering.
Repotting
When a plant becomes crowded in its pot, root binding restricts growth and reduces blooming. Repot into a larger container or divide the root mass. Hardy perennials often need dividing every 2–3 years.
Winter Care
Most plants we carry are winter-hardy perennials that can remain in the pond through Utah winters without intervention. Their foliage may die back to the waterline, but roots survive in the frozen pond and will regrow in spring.
Tropical floating plants (Water Hyacinth, Water Lettuce) cannot survive freezing temperatures. Remove them before the first hard frost. They can be overwintered indoors in a bright location with water, then returned to the pond the following May.
Each plant in our catalog has its USDA hardiness zone listed. Utah ranges from zone 4 at higher elevations to zone 8 in St. George. Verify your local zone before selecting plants you plan to overwinter in place.
Frequently Asked Questions
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