Vallisneria is the tall, ribbon-leaved background plant that spreads by runners. Tropica rates all three it sells as easy, with a low demand for light and CO2, which makes it a low-tech plant. Size is the thing to plan for. The giant form grows leaves long enough to lie across the surface.
Three types of Vallisneria
Shops sell several Vallisneria under names that say nothing about how big they get. Tropica lists three, and the gap between the smallest and the largest is the whole decision.
| Type | Leaves (Tropica) | What it suits |
|---|---|---|
| Vallisneria spiralis ‘Tiger’ | 30 to 50 cm long, 1 to 2 cm wide | Small aquariums |
| Vallisneria americana ‘Natans’ | 50 to 100 cm long, 1 cm wide | Fine, narrow leaves that shade little |
| Vallisneria ‘Gigantea’ | 50 to 150 cm long, 2 cm wide | Large aquariums only |
Tropica gives Asia as the origin of all three, including Vallisneria americana ‘Natans’, whose name suggests the Americas.
What it needs
| Requirement | Vallisneria |
|---|---|
| Light demand | Low |
| CO2 demand | Low |
| Difficulty | Easy |
| Growth rate | High for ‘Natans’, not rated for the other two |
| Placement | Stolon, background |
Tropica calls ‘Tiger’ an excellent plant for beginners that grows in virtually all light and water conditions, and ‘Natans’ a hardy plant for beginners. Neither needs added CO2, which is why Vallisneria turns up so often in low-tech tanks and in the Walstad method.
It spreads by runners
Vallisneria sends out runners with new plants along them, which is how a few plants become a back wall. Tropica says ‘Tiger’ forms runners easily and is thus easy to propagate, and that ‘Gigantea’ propagates through runners that are prolific if the bottom is nutritious.
That gives you a choice at setup. A nutrient aquasoil gets it spreading faster, and plain gravel slows it down. Either way, pull up the runners you do not want while they are small, and give away or bin the rest.
Mind the light it takes
The giant form is the one that causes trouble. Tropica says its leaves grow so long in most aquariums that they float on the surface, so the plant needs pruning to stop it taking too much light from plants growing beneath. That is the same problem floating plants create, except this one starts at the substrate.
The two smaller types are kinder to their neighbours. Tropica describes ‘Tiger’ as having narrow leaves that do not overshadow smaller plants, and ‘Natans’ as having fine, narrow leaves that do not overshadow other plants much.
Where it fits in a layout
Vallisneria is a background plant. Its height and its habit of filling space suit the jungle style, where overgrowth is the point, and it does the same job as an Amazon sword with a very different shape: ribbons instead of broad blades.
One more point in its favour for a stocked tank. Tropica says the leaves of ‘Gigantea’ are tough and strong, so they are not normally eaten by herbivorous fish.
Vallisneria questions
Does Vallisneria need CO2?
No. Tropica rates the CO2 demand of all three types as low, along with their light demand, which is what makes Vallisneria a standard choice for a low-tech planted tank.
How tall does Vallisneria get?
It depends which one you buy. Tropica gives ‘Tiger’ leaves of 30 to 50 cm, ‘Natans’ 50 to 100 cm, and ‘Gigantea’ 50 to 150 cm. In most tanks the giant form’s leaves reach the surface and lie along it.
Is Vallisneria good for beginners?
Yes. Tropica calls ‘Tiger’ an excellent plant for beginners, growing in virtually all light and water conditions, and describes ‘Natans’ as hardy and suitable for beginners. Buy for the size of your tank and thin the runners, and it asks very little else.
Sources: Tropica, Vallisneria spiralis 'Tiger'; Tropica, Vallisneria americana 'Natans'; Tropica, Vallisneria 'Gigantea'.