TankBud

One species · 11 forms

Rotala rotundifolia

Also known as Dwarf Rotala, Roundleaf Toothcup, Rotala rotundifolia 'Red', Red Rotala Rotundifolia

FreshwaterStemCuttingsSide shoots

Invasive. Regulated as an invasive aquatic plant in California and Louisiana. Never release into the wild; dispose of trimmings in the trash.

Rotala rotundifolia (Rotala rotundifolia)
Aquarium Plants Factory · Used with permission

Care at a glance

Light
Medium light
CO2
No CO₂ needed
Temperature
68–82°F
20–28°C
Max height
19.7 in
50 cm
Growth rate
Fast
Placement
Background
Type
Stem
pH
6.0–8.0
Hardness
4–15 dGH
Spread
2 in (5 cm)
Nutrient uptake
Root + water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Lythraceae
Origin
South, Southeast and East Asia

Pick a form

color follows light

Easygoing forms · any planted tank

High-color forms · strong light and regular trimming

What changes with the high-color forms

Easygoing formsHigh-color forms
LightMedium lightHigh light
Colorgreen with soft pink tipsorange to deep red (Platinum near white)
CO2optionalstrongly recommended

Underneath the color they are the same fast, skinny stem. The high-color lines were selected for red that only develops under strong light with iron on tap; in a modest setup they slide back toward green. Platinum is the exception, a near-white mutation that needs strong light and injected CO2 from the day it goes in.

Overview

Rotala rotundifolia is a classic, fast-growing stem plant for the background. It is an easy plant.

Did you know

The name rotundifolia means round-leaved, and it comes from the plant's emersed growth. Underwater the stems put out much narrower, green-to-pink leaves, the form hobbyists know.

Caring for Rotala rotundifolia

Push single stems of Rotala rotundifolia into the substrate a couple of centimeters apart, in the background. It is forgiving, and once acclimated it grows in low-tech tanks.

Medium light is enough, and it needs no injected CO2, though stronger light and CO2 give the best density. It feeds through roots and leaves, so root tabs and a liquid fertilizer both help. It handles 68 to 82°F (20 to 28°C) and a pH of 6 to 8.

Growth is fast, and untrimmed stems soon reach the surface. Cut side shoots free once they have a few leaves and plant them on their own.

All rotundifolia forms decide their color by conditions: light intensity first, then iron and how lean the water is on nitrate. The standard form stays green with pink tips in most tanks, while Colorata, Orange Juice and Blood Red were picked out precisely because they turn orange to crimson once the light is strong enough.

Rotala grows toward the light and bares its lower stems if left alone. Top the stems every couple of weeks, replant the cuttings in front, and the stand thickens into the dense bush the plant is famous for. It is nearly impossible to over-trim.

Ceylon is the old name for Sri Lanka, Wayanad is a district in Kerala, and Shimoga is a district in Karnataka. Manipurensis points to Manipur in northeast India, and Myanmar is a recent import from that country. H'ra came out of Vietnam, where it is also sold as Gia Lai. Each is a regional collection of the same species. Colorata, Orange Juice and Blood Red are nursery selections named for their color, and Platinum is a pale tissue-culture mutation. All of them are Rotala rotundifolia, whatever the shop tag says.

Good to know

Rotala rotundifolia is a member of the loosestrife family, Lythraceae. It grows as upright stems with opposite or whorled leaves rather than from runners. It is often confused with Rotala indica and sold under that name, but the two are distinct species.

In the wild

Rotala rotundifolia grows across South, Southeast and East Asia in swamps, ditches, riversides and rice paddies. In the wild it spends much of its life emersed in shallow, often soft to moderately hard water. It becomes fully aquatic only when the water rises.

Common questions

Which rotala stays red?

None of them is red on its own. The high-color forms other than Platinum hold red only under strong light with iron in the water. Blood Red goes the deepest, and it is also among the most demanding of the group.

Why is my rotala green at the bottom?

The lower leaves are shaded by the canopy above. Trim the tops and replant them; the fresh, well-lit growth carries the color.

Is rotala good for beginners?

Rotundifolia, Green and Shimoga are among the best first stem plants there are. Ceylon and Myanmar ask a little more, and the high-color forms are better saved for tanks with strong light and CO2.

Does Rotala rotundifolia need to be planted in the substrate?

Yes. Strip the leaves from the lower part of each stem, then push the stems into the substrate one at a time, a little apart.

Does Rotala rotundifolia need CO2?

No. Rotala rotundifolia grows well without added CO2.

How much light does Rotala rotundifolia need?

Rotala rotundifolia wants medium light. A light sold for planted tanks covers it.

Does Rotala rotundifolia need root tabs?

They help. Rotala rotundifolia takes nutrients through both its roots and its leaves. Root tabs near its roots and a liquid fertilizer cover both.

How do you propagate Rotala rotundifolia?

Rotala rotundifolia propagates by cuttings and side shoots. Cut off the top of a stem and replant it, and the stump left behind grows new shoots. Cut a side shoot off once it has a few leaves and plant it on its own.

How tall does Rotala rotundifolia grow?

Rotala rotundifolia grows to about 19.7 in (50 cm) tall. It grows fast, so expect to trim it often.

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