Vallisneria biwaensis

Vallisneria biwaensis is endemic to Lake Biwa, Japan's largest lake, where it has evolved in relatively cool, hard water over millennia. It is distinguished from other Vallisneria by its unusually wide, strap-like leaves that can reach 3–4 cm across and display attractive longitudinal veining. The leaf margins are often gently undulate, giving the plant a ruffled appearance unlike any other species in the genus. It is slower-growing and slightly more demanding than common Vallisneria species, preferring cooler water and consistent water chemistry. A rare find in the hobby, it rewards the patient aquarist with a genuinely distinctive and beautiful background plant.

Light: Medium (30–60 PAR); brighter light encourages the best leaf width and ruffling. CO2: Beneficial; supplementation improves growth rate and leaf quality significantly. Fertilisation: Root tabs every 2–3 months; regular liquid micronutrients and iron. Placement: Background specimen plant in large tanks; allow space for wide leaves to unfurl fully. Propagation: Produces runners, though more slowly than common Vallisneria; replant daughter plants carefully.