Alternanthera rosaefolia

Scientific name: Alternanthera rosaefolia

Family: Amaranthaceae

Usual maximum size in aquariums: 30 - 50 cm (11.81 - 19.69 inch)

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Recommended pH range for the species: 5.8 - 7.2

Recommended water hardness (dGH): 4 - 12°N (71.43 - 214.29ppm)

0°C 32°F30°C 86°F

Recommended temperature: 18 - 20 °C (64.4 - 68°F)

Reproduction of the plant: Cuttings

Origin (in the wild): South America

How fast these plants grow: Slow

Recommended substrate: Fine gravel

Demands on lighting: Bright

Ideal placement in a fish tank: Background

Common Names

Magenta Water Hedge

Origin

Alternanthera rosaefolia originates from South America, specifically thriving in the tropical Amazonian waterways. It grows in riverbanks and wetlands, adapting to both submerged and emerged conditions. Its versatility makes it a popular choice for aquarium enthusiasts and paludariums.

Quick Overview

• Ideal For: Aquariums, paludariums
• Difficulty Level: Medium
• CO₂ Requirements: Beneficial but not essential

Growing Conditions

Alternanthera rosaefolia grows best when fully submerged in aquariums, though it can also thrive in paludariums or humid, emerged conditions. This slow-growing plant requires bright lighting for optimal growth and coloration. Without adequate light, growth slows dramatically, and the lower leaves may drop over time. For best results, plant it in nutrient-rich fine gravel substrate, which supports healthy root development.

It thrives in a stable, slightly acidic to neutral pH range of 5.8 to 7.2 and moderate water hardness (4 to 12 dGH). While it can survive without CO₂ supplementation, adding CO₂ can significantly improve growth and boost its vibrant red coloration. It's especially helpful in high-light setups.

Planting Area

Given its height, reaching up to 50 cm (19.69 inches), Alternanthera rosaefolia is best placed in the background of larger aquariums. In smaller tanks, it can also serve as a midground plant, adding contrast and depth. When planted in groups along the back, it creates a striking visual effect. Make sure to leave enough space between plants to prevent overcrowding, which can hinder light penetration and airflow.

Propagation

Propagation is straightforward with Alternanthera rosaefolia. Simply take a healthy cutting from the middle shoot or side shoots, ensuring that the cutting has a few leaves. Plant the cutting in the substrate, where it will grow roots over time. Trimming regularly encourages bushier growth, which is beneficial for maintaining the plant’s shape and fullness.

Using nutrient-rich substrates and root tabs will help the new cuttings establish faster and ensure the mother plant stays in optimal health.

Difficulty

This species is of medium difficulty to care for. As long as it receives proper lighting and nutrients, it is relatively easy to maintain. However, in low-light conditions or without regular fertilization, growth will slow, and the plant’s vibrant red leaves may fade. Regular trimming and nutrient dosing are key to keeping this plant in prime condition.

Short Description

Alternanthera rosaefolia is highly valued for its stunning red and magenta-colored leaves, which provide a vivid contrast against green foliage in aquascapes. The stems have a reddish-purple hue, adding even more aesthetic appeal. This slow-growing plant adds depth and color to any tank, making it a favorite in Dutch-style and aquascaping setups.

To maintain its vivid coloration, regular fertilization with liquid nutrients or root tabs is essential. Iron, potassium, and other micronutrients are particularly important for preventing leaf discoloration. Although its growth rate is slow, its striking appearance more than compensates for the patience required. Its ability to grow submerged or emerged makes it a versatile choice for aquariums and paludariums.

Lighting Requirements

Bright lighting is essential for healthy growth. In traditional fluorescent lighting, bright is considered to be around 0.5 to 1 watt per liter (2 to 4 watts per gallon). For LED lighting, this translates to 30 to 40 lumens per liter (120 to 160 lumens per gallon). LED lighting is often preferred for its energy efficiency and lower heat output.

Insufficient light will slow the plant’s growth and cause its lower leaves to fall off. To ensure optimal health and coloration, aim for at least 8 to 10 hours of bright light per day. In high-light environments, adding CO₂ can further enhance growth and keep the plant vibrant and healthy.

Potential Issues

• Browning or Yellowing Leaves: Often caused by a lack of light or nutrient deficiencies, particularly iron or potassium. Address with proper fertilization and adequate light intensity.
• Poor Growth: Slow or stunted growth may be due to insufficient lighting or low nutrient levels. Make sure to provide enough micronutrients and maintain a stable pH for optimal results.
• Leaf Drop: Common in low-light conditions. Increasing light intensity and maintaining proper fertilization will help prevent leaf loss.

Overall Appeal

Alternanthera rosaefolia is a versatile, slow-growing plant that adds vibrant color and texture to aquariums and paludariums. Its striking red leaves make it a standout background plant in larger tanks, and with proper care, it can thrive for many years. Regular fertilization and bright lighting are essential to maintain its signature red hue, making it an excellent choice for aquascapers and hobbyists alike.