How to Grow Anacharis (Waterweed)
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Anacharis (Waterweed)
Egeria densa
aquatic plantAnacharis is a fully submerged aquatic plant with thin stems and small, bright green leaves arranged in whorls along the stem. It is one of the most popular oxygenating plants for aquariums and ponds, producing oxygen during photosynthesis while absorbing excess nutrients that would otherwise promote algae growth.
When should you plant Anacharis (Waterweed) in your zone?
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Example Anacharis (Waterweed) timeline · Pittsburgh, PA (Zone 6b)
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Plant Anacharis (Waterweed)
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Anacharis (Waterweed)
Late summer into fallBefore the first fall frost (≈ Nov 8)
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Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-10; most hardy in cooler climates (zones 3-7)
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Get my Anacharis (Waterweed) timeline →Growth Stages
Initial Establishment
1-2 weeksNewly planted cuttings develop roots from the nodes (where leaves attach); stems appear delicate with pale green coloration
Keep water gentle; avoid disturbance. Maintain consistent water parameters. Add liquid fertilizer to support root development.
Active Growth Phase
3-8 weeksStems elongate rapidly with new leaf whorls emerging; plant becomes bushy and denser
Provide 10-12 hours of light daily. Trim long stems to encourage branching. Monitor for nutrient deficiencies (yellowing leaves).
Mature Vegetation
Ongoing (months 3+)Plant reaches full size with thick, lush stems and dense foliage; deep green coloration
Regular pruning to control height and density. Remove dead or decaying leaves. Monitor for algae growth on surfaces.
Propagation
Continuous with mature plantsMature stems develop numerous side shoots and root nodes ready for separation
Cut healthy stems 4-6 inches long; remove lower leaves and replant immediately. Separated cuttings root within 1-2 weeks.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Reduce light duration to 8-10 hours; increase water changes (25-50% weekly); use algae-eating fish (Siamese algae eaters, otocinclus); add floating plants to shade water
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Remove manually; reduce feeding of fish to eliminate excess food snails feed on; introduce snail-eating fish (assassin snails); use snail traps
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and
(from plant decay)
Remove decaying plant material immediately; improve water quality with partial water changes; avoid overcrowding; maintain proper aquarium filtration
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Add all-in-one aquatic plant fertilizer weekly; use root tabs; ensure adequate lighting; test water for nitrogen, phosphorus, and potassium levels
Uses
Water Oxygenation
Aquatic ecosystemAnacharis produces oxygen through photosynthesis during daylight hours, improving water quality and creating a healthier environment for aquatic animals. This oxygen production helps prevent anaerobic conditions at the substrate level. [source]
Nutrient Absorption & Algae Control
Aquatic ecosystemThe plant absorbs excess nitrogen, phosphorus, and other nutrients that would otherwise feed algae blooms. This competitive nutrient uptake is one of the most effective natural methods for controlling unwanted algae in aquariums and ponds. [source]
Fish Shelter & Breeding
Wildlife habitatAnacharis provides dense vegetation where fish and invertebrates can hide, breed, and forage. It is especially valuable for fry (young fish) survival and for reducing stress in newly introduced fish. [source]
Live Food Production
AquacultureAnacharis-rich environments encourage the growth of microorganisms, zooplankton, and other microscopic organisms that serve as natural food sources for fish fry and filter-feeding invertebrates. [source]
Aquarium & Pond Decoration
HouseholdIts bright green, feathery appearance makes Anacharis an attractive aquascaping plant. It can be planted densely to create lush background areas or arranged in midground groupings for visual interest. [source]
Harvest Tips
Anacharis is harvested by cutting healthy stem sections 4-6 inches long using clean scissors. Cut just above a leaf whorl. Remove lower leaves before replanting cuttings in substrate or floating them in water until roots develop. Mature plants can be trimmed regularly (every 2-3 weeks) to encourage bushier growth and prevent them from overshadowing other plants.
Fun Facts
- 🌱 Anacharis is native to South America but has become invasive in many parts of North America, Europe, and Australia where it can choke waterways and outcompete native aquatic plants.
- 🌱 In the 1980s-1990s, Anacharis was widely marketed in aquarium stores as an 'elixir' for algae problems, becoming one of the most popular beginner aquatic plants worldwide due to its hardiness and ease of care.
- 🌱 Anacharis can survive and continue growing even if uprooted and left floating freely in water; it does not require soil or substrate to propagate, making it ideal for bare-bottom or sand-bottom aquariums.
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