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Mato Grosso Milfoil

Myriophyllum mattogrossense

Haloragaceae

PlantsDifficulty: ●●●○○Data: verified
Mato Grosso Milfoil — Myriophyllum mattogrossense
📷 Igor Balashov (iNaturalist user igor117) · CC BY 4.0 · resized · iNaturalist

About

Almost every photograph of a wine-red feathery stem plant sold as Myriophyllum mattogrossense is a photograph of something else. The true Mato Grosso milfoil is a South American plant with light green, three-dimensional whorls of hair-fine leaflets ringing a stem that may itself take on a reddish or bronze cast under a hard lamp — but the foliage stays green, and no amount of light, CO2 or iron will turn it red. The plant that does that is Myriophyllum tuberculatum, an Asian species sold under this name for roughly twenty years until A. E. Orchard untangled the two in the early 1990s, and still labelled 'M. mattogrossense Red' today. The difference matters at the till: the green species is medium difficulty and will grow in a medium-lit tank with no injected CO2 at all — though Flowgrow is equally clear that with stronger light and continuous CO2 it grows faster and forms bigger leaves, so the no-CO2 version is the slower, smaller version — while the red one is rated difficult, wants nearly twice the light and will not take hard water. A happy specimen carries broad, full whorls right up to the growing tip with short gaps between them. Read that tip for everything else. Whorls that come out smaller than the ones below mean nitrate or phosphate has hit zero; shoot tips that go white mean iron and trace elements have run out, and three independent references single out that white band as the species' warning light — because it grows so fast, it flags a shortage days before anything else in the tank reacts. Weak light makes it stretch rather than die: long internodes, thin whorls, a bare lower half. Treat the 0.5 W/l figure as a floor and not a target — Tropica and Aquasabi call the demand medium, but Flowgrow, Dennerle and Heimbiotop all rate it medium-to-high, so the requirement is contested and the safer reading is the brighter one. In the shop the whorls separate it from Cabomba, whose paired leaves lie in a flat fan; they do not separate it from Limnophila sessiliflora, which is whorled too, coarser in the segment, and the easier substitute.

Care

Plant single stems across the background 3-5 cm apart and plan on topping it weekly — neglected trimming, not deficiency, is what usually wrecks it: it hits the surface, shades its own base and goes bare below. Light starts at about 0.5 W/l, but take that as a minimum rather than an aim, because three of the reference databases call the demand medium-to-high. CO2 is the largest disagreement on this species — Tropica asks 6-14 mg/l, Flowgrow and Dennerle 20-40, a three-fold spread — and Flowgrow states outright that a medium-lit tank with no injection still grows healthy, large green whorls; run it without if you like, and expect a slower plant with smaller leaves. Hold nitrate near 10 mg/l and phosphate at 1-2 mg/l and dose iron and traces without gaps, because white shoot tips mean you stopped. In-vitro portions were grown out of water, so expect the lower whorls to melt and shed for the first two to four weeks: cut the healthy top, replant it, and bin the old base instead of nursing it. Carbonate hardness is contested too — Flowgrow and Aquasabi both stop at 10 dKH, only Heimbiotop stretches to 15 — so above roughly 10 dKH expect smaller whorls and slower growth rather than a dead plant, but also nothing resembling the catalogue photo.

Frequently asked questions

What water parameters does a Mato Grosso Milfoil need?
Mato Grosso Milfoil does best at 18–28 °C (64.4–82.4 °F), pH 5–7.5 and a general hardness of 0–30 °dGH.
Where should Mato Grosso Milfoil be placed in the aquarium?
Mato Grosso Milfoil works best at the back of the tank and reaches around 60 cm.
Is the Mato Grosso Milfoil suitable for beginners?
Mato Grosso Milfoil sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

Water & tank

Temperature18–28°C
Optimal temp.23–25°C
pH5–7.5
Hardness (GH)0–30°d
Carbonate (KH)2–10°d
Water typeFreshwater
FlowModerate
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