Vallisneria australis (Australian Eelgrass) Care Guide
Vallisneria australis is a tall ribbon-leaved Australian eelgrass (Hydrocharitaceae), a hardy background plant that spreads by runners across a wide pH range.
Compiled by Aquairi from published sources · Published · Updated
Overview
Vallisneria australis, the Australian eelgrass or ribbonweed, is a submerged perennial herb of the family Hydrocharitaceae with long, strap-like ribbon leaves. It is a hardy background plant for tall aquaria, spreading by stolons to form underwater meadows.
Taxonomy
- Family: Hydrocharitaceae
- Genus: Vallisneria
- Scientific name: Vallisneria australis
- Common names: Australian eelgrass, ribbonweed, eelweed
Habitat
The species occurs in freshwater lakes, rivers and irrigation channels in Australia. It is a tufted, stoloniferous perennial whose linear leaves reach up to about 3 m long and 11-35 mm wide. The genus is dioecious, with male and female flowers on separate plants and female flowers reaching the water surface on long stalks.
Tank requirements
- Temperature: 16-28 °C (61-82 °F)
- pH: 6.5-8.2
- GH: 5-18 °dGH
- Maximum height: up to 100 cm
- Lighting: medium
- CO2: not required
- Placement: background
Growth and care
Growth is fast and the plant is undemanding, tolerating cool to warm and moderately hard water across a wide pH range. The long leaves suit tall display tanks where they can reach the surface without being trimmed.
Propagation
It propagates vegetatively through runners, producing daughter plants at the nodes that can be separated and replanted.
Propagating Vallisneria australis (Australian Tape Grass)
Overview
Vallisneria is a submerged rosette plant whose leaves arise in clusters from the roots, with rounded tips and raised veins. Vallisneria australis, the Australian tape grass, is a giant form whose ribbon leaves can exceed one metre, making it a striking background plant for tall display tanks.
It is a fast-growing root feeder that does best under bright illumination but still grows, more slowly, under moderate light. It does not require CO2 and tolerates neutral to alkaline, moderately hard, cool-to-warm water, disliking very acidic conditions.
Propagation Method
Vallisneria spreads by runners, producing daughter plants at the ends of those runners. Propagation means letting these daughter rosettes form and then cutting them away to transplant, rather than topping or cutting the leaves of the parent. Over a few months the runners knit the substrate into dense growth.
Step-by-Step
- Plant a parent rosette in a back corner and let it establish.
- Wait for runners to push out across the gravel and form daughter rosettes at their tips.
- Once a daughter rosette has its own leaves and roots, cut the connecting runner.
- Lift the daughter plant and replant it where you want new growth, keeping the crown at substrate level and the roots buried.
- Feed and light it well so it roots in and sends out its own runners.
Conditions for Healthy Growth
- Lighting: a high-quality planted-aquarium LED; brightest growth under strong light, slower under moderate light.
- Feeding: it is a root feeder and must be fed, for example with an all-in-one fertiliser or in tanks with a heavy fish load; plain gravel works if iron-rich fertiliser is added.
- CO2: not required.
- Water: neutral to alkaline, moderately hard; pH about 6.5-8.2, GH 5-18, temperature 16-28 C; it dislikes very acidic water.
- Crown: keep the crown at the substrate surface so it is not buried.
Maintenance
Once established it will keep spreading through the gravel, so thinning is the main task. Pull up stray daughter plants where you do not want them and replant or share the excess; the plant is easy to remove and propagates fast enough that hobbyists routinely have spares to give away.
Common Challenges
- Underfeeding: as a root feeder it will languish without fertiliser, especially in lean substrates.
- Buried crown: planting the crown too deep can rot the plant; keep it at substrate level.
- Spreading too far: vigorous runners will colonise the whole tank unless you thin them, though they are easy to pull out.