The Hydrocotyle (Pennywort) Care Guide: Four Plants, Four Habits

Four plants share the name pennywort and they behave so differently that advice for one will ruin another. One carpets, one floats, one stands up on stalks, and one does whatever the light tells it to. Sort out which Hydrocotyle you have before you plant it.

Hydrocotyle tripartita — the carpet

Small three-lobed leaves on thin runners, sold as 'Japan' or 'sp. Japan'. Under strong light it hugs the substrate and knits into a dense carpet in six to eight weeks; under moderate light it grows upward and sideways into a loose tangle. Light intensity is the whole difference. CO2 is not strictly required, but without it the carpet stays thin and takes far longer to close.

Trim by hand rather than with scissors alone: pull out the runners that have climbed on top of the mat, then cut what is left flat. Trimmed pieces root wherever they touch soil, so scatter them into gaps. Left alone for two months it will smother anything shorter than itself, including hairgrass.

Hydrocotyle leucocephala — Brazilian pennywort

The easy one. Round, scalloped leaves on a fast stem that grows towards the surface and is perfectly happy floating once it gets there. Low light is fine, CO2 is irrelevant, and it pulls nitrate out of the water column faster than most stem plants. Plant it and it climbs; float it and it spreads across the surface with roots hanging down. Both are legitimate. The 'Marble' form carries cream variegation and wants slightly more light to hold the pattern.

Its fault is speed. Weekly trimming is normal in a well-lit tank, and it will shade everything below it if left to run.

Hydrocotyle verticillata — umbrella pennywort

Round, coin-shaped leaves held flat on vertical stalks, like tiny lily pads on sticks, spreading by runner. It looks delicate and it is the most demanding of the four: it wants high light directly overhead and will stretch, pale and shed leaves if it does not get it. Plant the runner shallowly, one node at a time, and give it space — it looks best as a scattered accent rather than a mass. The 'Small Size' form stays proportionally shorter and is the one to choose for anything under 20 gallons.

Hydrocotyle sibthorpioides — dwarf pennywort

Tiny lobed leaves and a fine creeping stem, sometimes confused with tripartita. Given bright light it will carpet, but it has a stronger instinct than tripartita to head for the surface, and in moderate light it forms a floating mat rather than a lawn. If you want it on the substrate, weigh it down and light it hard. It is also a good choice for a shallow or emersed setup, where it stays naturally low.

The pattern behind all four

Every Hydrocotyle wants to reach the surface. The carpeting species can be argued out of it with light; the stem species cannot and should not be. Decide which behaviour you want before you buy, and match the species to it rather than fighting the plant.

Quick reference

• Light — Low (leucocephala) to high (tripartita, verticillata, sibthorpioides as carpet)
• CO2 — Optional; needed for a tight tripartita carpet
• Water — 68–82°F, pH 6.0–7.5, undemanding on hardness
• Substrate — Nutrient substrate for carpeting species; leucocephala can float
• Placement — Foreground carpet, midground accent, or surface cover depending on species
• Growth rate — Fast
• Propagation — Runners and cuttings; every node roots
• Difficulty — Beginner (leucocephala) to intermediate (verticillata)

Hydrocotyle we stock

• Hydrocotyle tripartita Vitro Culture — the carpet
• Brazilian Pennywort and Brazilian Pennywort Marble
• Hydrocotyle verticillata (Umbrella Pennywort), 'Small Size', and Vitro Culture
• Hydrocotyle sibthorpioides (Dwarf Pennywort) — also as Vitro Culture

Keep reading

• Best Carpet Plants for Aquariums — where tripartita sits against hairgrass, Monte Carlo and the rest
• Best Floating Plants for Freshwater Aquariums — if you are floating Brazilian pennywort, this is the company it keeps