How to Grow Red Alternanthera

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Red Alternanthera

Alternanthera reineckii 'Red'

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A vibrant aquatic or semi-aquatic ornamental plant prized for its striking deep red to burgundy foliage, particularly on the undersides of leaves. This cultivar of Alternanthera reineckii is popular in aquascaping and tropical gardens for adding dramatic color contrast. It can grow both fully submerged in aquariums or partially submerged in wet soil conditions.

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Example Red Alternanthera timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Red Alternanthera

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Red Alternanthera

    Around May 17

    ≈ 30 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Red Alternanthera dates for your own zip code.

Growing Conditions

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Sun: Bright indirect light, 8-12 hours daily; benefits from moderate to high lighting in aquariums (0.5+ watts per liter); full sun to partial shade for terrestrial growth
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Water: Requires consistently moist to wet conditions; for aquatic growth, water temperature 72-82°F (22-28°C) is ideal. In aquariums, maintain stable water parameters with regular water changes. If grown as semi-aquatic, keep soil constantly moist but not waterlogged.
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Spacing: 4-6 inches between plants for bushy development inches
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Days to maturity: 30-60 days to significant growth; full coloration develops over 6-8 weeks under optimal conditions
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Planting depth: Plant stem cuttings 1-2 inches deep; allow roots to develop before planting fully. For aquatic planting, secure stems in substrate with weights if needed.

Soil

Type: Nutrient-rich, well-draining substrate (aquarium soil, peat-based, or loamy garden soil)
pH: 6.0-7.5
Amendments:
Aquarium plant fertilizer (nitrogen, phosphorus, potassium) Trace minerals and micronutrients Peat moss or organic matter for aquatic conditions

Growing Zones

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Thrives in zones 10-12; can be grown as an annual in cooler zones or indoors year-round

10 11 12

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Growth Stages

1

Cutting/Propagation

1-3 weeks

Freshly cut stems with 2-3 leaf nodes, initially pale green, roots beginning to develop

Keep in warm water (75-80°F) with good light. Change water every 2-3 days to prevent rot. Roots should appear within 1-2 weeks.

2

Establishment

2-3 weeks

Roots established, new leaves emerge, plant begins to acclimate to growing medium, coloration starts to develop

Ensure stable water conditions and consistent nutrient supplementation. Provide adequate lighting to encourage color development. Plant should be firmly rooted.

3

Vegetative Growth

4-8 weeks

Stems elongate, leaves multiply along stems, red coloration intensifies particularly on leaf undersides

Feed regularly with liquid fertilizer; in aquariums, use comprehensive plant fertilizers. Maintain bright lighting. Prune upper stems to encourage bushier lateral growth.

4

Mature Plant

Ongoing

Full-grown stems 6-12+ inches tall, dense foliage, vivid red undersides, vibrant green to red upper leaf surfaces

Continue regular fertilization and water changes. Trim regularly to maintain shape and encourage bushiness. Remove any yellowing or damaged leaves.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Allelopathic plants that may inhibit growth (limited concern for Alternanthera)

Common Pests

  • Increase water circulation and light quality; reduce excess nutrients; perform regular water changes; use algae-eating fish or invertebrates (Amano shrimp, otocinclus catfish); use UV sterilization in severe cases

  • Increase humidity and water spray; inspect regularly; isolate affected plants; use insecticidal soap if severe; ensure good air circulation

  • Remove by hand with cotton swab dipped in alcohol; isolate affected plants; spray with neem oil or insecticidal soap; repeat treatment every 7-10 days

  • Use comprehensive aquarium or hydroponic fertilizer; adjust dosing based on plant response; ensure adequate lighting; test water parameters regularly

Uses

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Aquarium Decoration & Planted Tank Focal Point

Household

Red Alternanthera is a premier choice for freshwater aquascaping, used as a mid-ground or background plant to create striking visual contrast with its deep red coloration. Its vibrant color adds dramatic aesthetic appeal to planted tanks and biotope aquariums. [source]

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Terrarium & Paludarium Plant

Household

Excellent for semi-aquatic terrariums and paludariums where it can grow partially submerged, thriving in high-humidity tropical environments with wet substrate. The plant adds color and structure to moisture-rich display tanks. [source]

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Tropical Landscape & Container Gardening

Craft

In warm climates, Red Alternanthera serves as an ornamental foliage plant for tropical gardens, containers, and mixed plantings. Its compact, colorful growth habit makes it ideal for border edging and color accent roles. [source]

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Fish & Aquatic Life Habitat

Wildlife

Provides shelter, food sources, and spawning substrate for aquarium fish fry and invertebrates. Dense growth creates microhabitats beneficial for shrimp, small fish, and biofilm-feeding organisms. [source]

Harvest Tips

For propagation, take 2-3 inch stem cuttings just above a node using clean scissors. Cuttings can be taken at any time during active growth. Remove lower leaves from cuttings before placing in water or substrate. Trim mature plants regularly to encourage bushiness; discarded stems can be re-propagated.

Fun Facts

  • 🌱 The vivid red coloration of Alternanthera reineckii 'Red' is enhanced by high light intensity and nutrient availability; under low light, plants often revert to green, demonstrating remarkable phenotypic plasticity.
  • 🌱 Red Alternanthera is native to South America and is distantly related to amaranth and celosia; it belongs to the Amaranthaceae family despite its popularity in aquatic settings.
  • 🌱 In optimal aquatic conditions, this plant can grow 1-2 inches per week, making it one of the faster-growing stem plants used in high-tech planted aquariums.

Gardening Terms

New to gardening? Learn about terms used in this guide:

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