Vallisneria americana 'Gigantea'

Vallisneria americana 'Gigantea' is one of the largest aquarium plants available, with ribbon leaves that can exceed 1 m in length in large tanks. The leaves are flat, wide (up to 2 cm), and a rich mid-green, creating an impressive curtain effect along the back wall of large display aquariums. A single established clump can fill the entire back of a large tank.

This giant form of V. americana is extremely vigorous and grows rapidly with adequate light, nutrients, and root fertilisation. It tolerates a wide range of water conditions including moderately hard, alkaline water — making it suitable for Rift Lake cichlid tanks, large goldfish setups, and other high-pH environments where many plants fail. CO2 supplementation is beneficial but not required.

Despite its size, 'Gigantea' is straightforward to keep. It spreads via runners and will naturalise a large tank background over time. The main management requirement is trimming — long leaves will reach the surface and then grow along it horizontally if not periodically shortened, which is done by cutting individual leaves to the desired height.

Light: Low to medium; large leaf area uses light efficiently — even subdued light sustains steady growth. CO2: Not required; grows vigorously in CO2-free environments given adequate root nutrition. Fertilisation: Root tabs are essential for sustained growth; this is one of the most root-dependent plants in the hobby. Placement: Plant in deep substrate at the back of large tanks (100+ L); allow significant horizontal spread. Propagation: Detach runner plantlets once they have 6+ leaves; plant immediately at 10–15 cm spacing.