Pearl Weed

Pearlweed originates in North America, specifically the Southeastern Atlantic coast, where it grows in shallow river mouths and muddy shores, forming dense carpets. A highly versatile aquarium plant of medium height, delicate stems, and oblong leaves, it spreads rapidly and requires maintenance to keep it from taking over a tank. It makes a wonderful carpet for neocaridina shrimp to graze on, hide in, and spawn in, as well as being good for live-bearing fish and egg laying fish, providing cover for the fry and eggs. It's name, Pearlweed, comes from the tiny air bubbles, also known as "pearls" that its leaves produce during optimal photosynthesis.

  • Scientific name: Hemianthus Micranthemoides, Micranthemum Micranthemoides, Hemianthus Glomeratum, Micranthemum Glomeratum -- all four Latin names are used interchangeably for the same plant
  • Plant type: Stem plant, rooting in substrate, frequent trimming to keep under control, height of 4 to 5 inches unless trimmed to be a shorter carpeting ground cover 1 to 2 inches high
  • Water parameters:
    • pH range: 6.5 to 7.5, but can adapt to a wider range (5.0 to 8.0)
    • Temperature range: 65F to 82F, though it can survive in cooler water down to 41F with significantly slowed growth
    • Water hardness: 1 to 20 dGH (90-357 ppm), 1 to 15 dKH (70-140 ppm), adapts to both soft and hard water
    • Stability, consistency more important than chasing any "perfect" numbers
  • CO2 requirements: recommended for carpeting or bushier growth
  • Substrate preference: almost any substrate, sand, gravel, but nutrient rich aqua soil is best
  • Nutrient requirements: While it can root in substrate, it is also an efficient water column feeder, so regular liquid fertilization can be helpful
  • Lighting
    • High light encourages horizontal creeping growth, forming a dense foreground carpet
    • Medium to low light causes the plant to grow vertically toward the surface, making it better for midground
  • Water flow: Moderate, gentle but thorough with good CO2 and nutrient distribution, airstone for oxygen at night
  • Propagation: Pearlweed propagates easily by planting stem cuttings in the substrate, where they quickly root and grow new shoots, while the parent plant also branches out where cut for trimming, cut above an internode (where leaves meet the stem) and replant the top section or a small bunch of stems into substrate to grow new plants, it can be planted horizontally or vertically
  • Filtration: Clean water is essential, with proper balance of nutrients, oxygen, co2, moderate to high light, like most aquatic plants, weekly 25% water changes, monitor water conditions regularly
  • Acclimation period and getting established
    • New growth and shoots emerging within days of planting or starting from cuttings
    • Melting: Expect pearlweed to melt (lose leaves) initially as it adjusts to the new tank parameters, but it should bounce back quickly
    • Rooting: It can take 6 to 9 weeks for plants to establish strong root systems
    • Rapid spread: Once established, pearl weed grows very fast, potentially spreading 5 to 8 inches per month, making trimming necessary every couple weeks
    • Factors influencing growth rate
      • Adding CO2 speeds up dense carpet growth, but grows vertically without CO2
      • High light encourages compact carpet growth, while low light makes it reach upward for light
      • Good aqua soil substrate, root tabs, and liquid fertilizer fuel faster growth
      • Stable water parameters with cycled tank are crucial for fast, healthy growth
    • Summary: Expect some new growth within days, but established carpeting usually takes a couple of months

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