Potamogeton pusillus
Potamogeton pusillus · Potamogetonaceae
The gardener's calendar
Ideal time to plant potamogeton pusillus: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Common name
- Slender Pondweed
- Family
- Potamogetonaceae
- Type
- Submerged aquatic plant
- Natural habitat
- Temperate and cold freshwater in Europe and Asia
- Height
- 10 to 30 cm tall
- Growth
- Fast to moderate
- Hardiness
- Very hardy, down to -15 °C
- Foliage
- Persistent, fine linear and supple leaves
Care
Submersion and water circulation
Slender pondweed must remain fully submerged in fresh water. Favour slightly flowing water or well-oxygenated water (through aeration or filtration) to promote growth. Avoid prolonged stagnant water, which would encourage stem rot. Regular water changes are beneficial, especially in an aquarium or small pond.
Light and depth
This plant appreciates moderate to good light, ideally 8 to 10 hours per day. In a natural pond, plant it between 30 and 60 cm deep for sufficient light exposure. It tolerates semi-shaded areas but grows more vigorously in bright light.
Substrate and anchoring
A light nutritive substrate (peat, aquatic soil or enriched fine sand) facilitates rooting. Slender pondweed develops equally well in poor or enriched soil, but appreciates moderate organic matter. Ensure good anchoring to prevent the plant from floating.
Moderate nutritional input
A diluted aquatic fertiliser, applied monthly, supports growth without excess. Do not overdose: excessive input promotes unwanted filamentous algae. Natural input from organic debris can be sufficient in a balanced pond.
Cutting and growth control
Regularly trim overly long stems or those becoming invasive, especially in an aquarium. Cut 5 to 10 cm below the surface to encourage lateral branching. Remove dead or degraded parts to maintain good density.
Problem prevention
Slender pondweed is little subject to disease if water conditions are good. Watch for stem rot, often due to overly stagnant or organic-rich water. Well-oxygenated water and regular circulation limit these issues.
Did you know?
Slender pondweed is an excellent natural oxygenator for aquariums and small ponds: its fine submerged leaves release dissolved oxygen directly into the water, earning it the nickname 'aquatic lung'. In nature, these small plants play a key role in the stability of freshwater ecosystems, providing refuge for fry and food for aquatic invertebrates.
Where to buy it
Best planted in spring or autumn, away from frost and heatwaves. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September, October.
Add this plant to my garden →Plants from the same family
- Stuckenia pectinataStuckenia pectinata
- Potamogeton perfoliatusPotamogeton perfoliatus
- Zannichellia palustrisZannichellia palustris
- Bog pondweedPotamogeton polygonifolius
- Potamogeton berchtoldiiPotamogeton berchtoldii
- Potamogeton gramineusPotamogeton gramineus
Tips generated and checked by Viridia — adapt them to your local climate.