What Plants Help Keep Algae Out of Natural Swimming Pools?

When homeowners choose a natural swimming pool, they expect crystal-clear water without relying on harsh chemicals. While the beauty of a natural pool comes from its ecosystem, one essential part of that system is the plants—especially the ones that help control algae naturally. These anti-algae plants for natural swimming pools don’t just look beautiful; they actively improve water clarity and keep your pool healthy year-round.

At Reflections Water Gardens, we design natural swimming pools using carefully selected aquatic plants that support filtration, oxygenation, and biological balance. In this guide, we break down the best natural pool cleaning plants, how they work, and which ones are most effective at preventing algae growth.

Why Algae Forms in Natural Swimming Pools

Before choosing plants, it’s important to know what causes algae in the first place.

Algae grows when three things are present:

• Sunlight

• Nutrients (like nitrates and phosphates)

• Warm, still water

You can’t remove sunlight, but you can remove the nutrients algae feeds on—and that’s where water clarity plants play a huge role.

The right plants absorb excess nutrients, oxygenate water, and block sunlight penetration, creating an environment where algae struggles to survive.

Best Anti-Algae Plants for Natural Swimming Pools

Here are the top plant categories and species that help keep algae under control in natural pools:

1. Submerged Oxygenating Plants

These plants grow entirely underwater and continuously release oxygen into the water—boosting healthy bacteria and starving algae of nutrients.

Best Choices

• Hornwort (Ceratophyllum demersum)

• Anacharis / Elodea (Egeria densa)

• Waterweed (Hydrilla verticillata)

• Vallisneria (Eelgrass)

Benefits

• Absorb nutrients that algae needs

• Improve oxygen levels

• Clear water naturally

• Grow easily and require minimal maintenance

2. Floating Plants

Floating plants reduce algae by blocking sunlight and absorbing nutrients through their roots, which hang beneath the surface.

Best Choices

• Duckweed (for large regeneration zones)

• Water Lettuce

• Water Hyacinth (check local regulations; restricted in some states)

Benefits

• Shade the water

• Compete with algae for nutrients

• Help regulate water temperature

3. Marginal Plants (Shallow Edge Plants)

These are planted along the pool’s edges or shallow regeneration zones. They help filter nutrients from the water before algae can access them.

Best Choices

• Pickerel Rush

• Water Iris (Yellow, Blue, or Japanese Iris)

• Sweet Flag (Acorus calamus)

• Cattails (narrowleaf varieties)

Benefits

• Strong natural filtration

• Add structure and beauty to natural pools

• Help stabilize water ecosystem

4. Phytoremediation Plants (Heavy Nutrient Absorbers)

These are high-performance nutrient sponges that suck up nitrates, organic debris, and pollutants—perfect for algae prevention.

Best Choices

• Water Mint

• Parrot Feather

• Swamp Lily

• Lizard’s Tail

Benefits

• Prevent nutrient buildup

• Improve water clarity

• Encourage beneficial microbial activity

Table: Best Plant Types for Algae Control in Natural Swimming Pools

Plant Type	Examples	Main Benefits	Best Placement
Submerged Oxygenators	Hornwort, Elodea, Vallisneria	Increase oxygen, absorb nutrients, improve clarity	Deep or mid-depth regeneration zones
Floating Plants	Duckweed, Water Lettuce	Reduce sunlight, cool water, block algae growth	Surface of shallow areas
Marginal Plants	Pickerel Rush, Water Iris, Sweet Flag	Natural filtration, nutrient removal	Edges and shallow shelves
Phytoremediation Plants	Water Mint, Swamp Lily	Absorb nitrates & organic debris	Regeneration shelves & shallow areas

How These Plants Work Together to Prevent Algae

A balanced natural swimming pool uses different plant types working as a mini ecosystem. Here’s how they control algae:

1. Removal of Nutrients

Aquatic plants absorb the excess nutrients algae feed on.

2. Increased Oxygen Levels

Oxygenating plants promote aerobic bacteria, which break down organic debris.

3. Shading

Floating plants prevent excessive sunlight from fueling algae growth.

4. Filtration

Marginal plants act as natural biological filters.

5. Water Movement

Plants interact with the water flow systems to prevent stagnation.

When combined with proper design, these plants create a self-regulating environment that naturally keeps water clear.

How Many Plants Do You Need for Algae Control?

Generally, 50–60% of your regeneration zone should contain aquatic plants.

A balanced mix is best:

• 30% submerged oxygenators

• 20% marginal plants

• 10% floating plants

• 10% phytoremediation specialty plants

The exact mix depends on your climate, water chemistry, sunlight exposure, and pool design.
Reflections Water Gardens uses ecosystem-based design to calculate the ideal planting ratios for long-term water clarity.

Extra Tips to Prevent Algae in Natural Pools

Beyond plant selection, here are additional steps that help keep water crystal clear:

Maintain Good Water Circulation

Stagnant zones encourage algae.

Use a Skimmer

Removes organic debris before it decomposes.

Control Sun Exposure

Strategic landscaping can add shade.

Avoid Overfeeding Fish (if applicable)

Fish waste increases nutrient levels.

Choose a Professional Natural Pool Builder

A well-designed regeneration zone reduces algae naturally without constant intervention.

Final Thoughts

The key to preventing algae in a natural swimming pool is selecting the right anti-algae plants for natural swimming pools and designing a balanced ecosystem. Using a mix of oxygenators, floating plants, marginal plants, and nutrient-absorbing species ensures long-term clarity, beauty, and low-maintenance swimming.

Reflections Water Gardens specializes in crafting natural pools that stay clear naturally—without chemicals—using proven plant-based water purification systems.

If you’re planning or upgrading a natural swimming pool, the right plant strategy can make all the difference in creating a crystal-clear, algae-resistant oasis.