Roundleaf Lindernia

About

A weed in the best sense - but a weed with a maintenance bill. Keeping it alive is not the hard part; the question is what shape it takes and how much scissor work that shape costs. Happy, it is a dense green mound: thin, broadly ovate to almost round leaves 1.5-2 cm long and 0.9-1.3 cm wide, in opposite pairs about 2.5-3.5 cm apart on shoots roughly 2.5-3.5 cm wide, branching again and again until the group closes up (Aquasabi's measurements). The leaves are thin enough to see light through and a pale vein pattern stands out on the blade. That branching is the tell that the light is right. Light is where the sources fight, and the fight is lopsided. Tropica's card rates the demand LOW, and the shops that reprint Tropica's card - Aquarium Gardens among them - repeat it. Every source that wrote its own text disagrees: Flowgrow says 'mittel bis hoch', Aquasabi medium, Garnelio 'medium to high', Aquatic Arts 'moderate to high' with the explicit note that it 'will grow at a slower pace under low lighting'. We publish medium, and it is a shape control rather than a survival threshold: under weak light the shoots grow strictly upright, stretch their internodes and barely branch (Aquasabi), leaving thin single stems that go bare at the base. That is the common failure and it does not look like damage, which is exactly why keepers miss it - judge this plant by how much it branches, not by how its leaves look. The failure mode nobody warns about is the opposite of melting: it lets go. Aquasabi is blunt - tall, old bushes are often poorly rooted and can detach from the substrate. A group left to run past 40 cm builds more top than root and lifts off the bottom in one mat, usually during a water change. The 15-30 cm trim height on every care sheet is not cosmetic, it is what keeps the plant anchored. There is no red form and no conditional colour here, but there is a conditional pattern: most stock in the shops, including Tropica's 045, is the lightly marbled 'Variegated' clone with white longitudinal veins, and it reverts. Entirely green shoots appear, outgrow the marbled ones and take the group over unless you cut them out - Tropica and Glass Box Diaries report this independently. Two labels to distrust in the shop. First, Bacopa monnieri: the two are still conflated in trade, and one live listing is titled 'Water Hyssop (Lindernia rotundifolia)' while its description is Bacopa monnieri's word for word. Bacopa leaves are thick, succulent and spoon-shaped with venation you can barely see; Lindernia leaves are thin, round-ovate, clearly veined, smaller and packed far more densely on bushier stems. Growth settles it too - every source that rates this plant calls its growth fast, while Flowgrow rates Bacopa monnieri's growth 'mittel'. Second and more expensive: Lindernia sp. 'India'. Do not read the shared genus word as a promise of the same easy plant. Flowgrow says it 'shows the most resemblance to Lindernia rotundifolia', differing mainly by light purple leaves on green stems and a strictly upright, barely branching habit - and then calls it 'quite demanding', recommending a constant supply of CO2, macro- and micronutrients and soft water. Same genus, same silhouette, a completely different budget.

Care

Medium light, roughly 20-90 PAR, read as a shape control rather than a survival threshold: it stays alive under low light, it just grows leggy and unbranched there, and Aquatic Arts adds that it slows down as well. Only Tropica's card rates the demand low; Flowgrow, Aquasabi, Garnelio and Aquatic Arts all put it at medium or medium-to-high. CO2 is optional - Aquasabi and Garnelio both say it is not necessary but greatly accelerates a plant that is already fast, Flowgrow's band for injected tanks is 10-40 mg/l, and Tropica calls the demand medium, which on its own scale means only 6-14 mg/l. Feed the water column properly rather than token-dosing: a fast stem plant under medium light is a real consumer, and Aquatic Arts names 'clean, nutrient-rich water' as its one requirement. Do not chase Flowgrow's NO3 10-50, PO4 0.1-3, K 5-30 and Fe 0.01-0.5 quartet - those same four numbers appear on Flowgrow's Bacopa monnieri entry, so they are the site's default set and not a measurement of this species. Water chemistry is close to irrelevant: pH 5-8, KH 0-14, GH 0-30 (Aquasabi is the only source cited here that publishes a GH figure at all). Temperature does need care. Flowgrow's and Aquasabi's tables both print a 4-34 C tolerance, but Aquasabi's own prose says 'below 20 to 30 C' and every retail source gives 18-28 C, so we publish 18-30 C with 22-26 C optimal - a cool room tank slows this plant rather than suiting it. The real work is scissors: keep it at 15-30 cm and replant the tops before the group passes 40 cm, goes bare at the base and detaches from the substrate. On marbled stock, cut out any entirely green shoot in the week you first see it.

Diet

Takes most of what it needs from the water column and some through its roots, so a plain inert substrate is fine as long as the column is dosed - but do dose it, because this is a fast grower rather than a low-demand one. A shortage does not show as holes, spots or yellowing here; growth simply slows, and Glass Box Diaries reports the plant still growing well in lean tanks and only accelerating when more is available. Measure a week of new growth rather than reading the leaves - and do not confuse this with the branching signal, because how much it branches is set by light, not by fertiliser.

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Frequently asked questions

What water parameters does a Roundleaf Lindernia need?

Roundleaf Lindernia does best at 18–30 °C (64.4–86 °F), pH 5–8 and a general hardness of 0–30 °dGH.

Where should Roundleaf Lindernia be placed in the aquarium?

Roundleaf Lindernia works best in the midground and reaches around 50 cm.

Is the Roundleaf Lindernia suitable for beginners?

Yes — Roundleaf Lindernia is one of the easier species to keep and forgives typical first-tank mistakes, as long as the aquarium is cycled and maintained.

Sources

• Lindernia rotundifolia - Rundblättriges Büchsenkraut - Flowgrow Wasserpflanzen-Datenbank (PRIMARY, German)
• Lindernia rotundifolia - Tropica Aquarium Plants (article 045)
• Lindernia rotundifolia 'Variegated' | Aquasabi - Aquascaping Shop
• Lindernia rotundifolia - Aquarium Gardens (UK)
• Round-leaved boxwort - Lindernia rotundifolia - Tropica pot | Garnelio (EN)
• Lindernia Rotundifolia Care Guide - Glass Box Diaries
• Roundleaf Lindernia (Lindernia rotundifolia) Tissue Culture - Aquatic Arts
• Water Hyssop (Lindernia rotundifolia) - My Home Nature (live mislabelling example)
• Lindernia sp. 'India' - Flowgrow Aquatic Plant Database