Monte Carlo

Micranthemum tweediei

Also known as Micranthemum sp. 'Monte Carlo', New Large Pearl Grass, Bacopa sp. 'Monte Carlo'

FreshwaterCarpetingCuttingsSide shoots

Monte Carlo (Micranthemum tweediei) — Yercaud-elango · CC BY 4.0

Care at a glance

Light: Medium light
CO2: CO₂ beneficial
Temperature: 68–82°F; 20–28°C
Max height: 2 in; 5 cm

Growth rate: Medium
Placement: Foreground
Type: Carpeting
pH: 5.5–7.5
Hardness: 2–15 dGH
Spread: 3.9 in (10 cm)
Nutrient uptake: Root + water column
Growth region: Submersed or emersed
Difficulty: Easy
Family: Linderniaceae
Origin: South America (Argentina)

Overview

Monte Carlo is the go-to beginner carpeting plant, an easy creeper that covers the foreground in a low green mat.

Did you know

Monte Carlo spent years in the trade as a mystery plant labeled Micranthemum sp. 'Monte Carlo' after the importer. Only later was it identified as the long-described species Micranthemum tweediei.

Caring for Monte Carlo

Split the mat into small portions and push each one into the substrate with tweezers, leaving gaps for it to fill. Pin the creeping stems flat so they root in and run sideways. Monte Carlo moves smoothly from emersed-grown nursery stock to a submerged carpet.

It carpets reliably under medium light without CO2. With CO2 and a nutrient-rich substrate it grows denser, more compact and noticeably faster. It feeds through its roots and from the water, so root tabs and a liquid fertilizer both help.

Monte Carlo grows at a moderate pace to about 2 in (5 cm) tall. As the carpet thickens, the lower layers can detach and float up. Trim it regularly to keep it thin and well anchored, and remove trimmings promptly, since loose pieces re-root anywhere.

Good flow and clean water help it stay green rather than collecting algae or debris. Keep the water at 68 to 82°F (20 to 28°C).

Good to know

Monte Carlo is a small creeping member of the family Linderniaceae. It has compact round leaves on prostrate stems that root down at the nodes as they spread. It is larger-leaved and easier to keep than its close relative Micranthemum sp. 'Cuba' (Hemianthus callitrichoides). Shops still sell it under provisional names such as New Large Pearl Grass and Bacopa sp. 'Monte Carlo'.

In the wild

Monte Carlo comes from Argentina in South America, where it grows along the wet margins of streams and on seasonally flooded ground. It lives a semi-aquatic life, creeping over damp soil emersed and switching to a submersed habit when the water rises.

Common questions

Does Monte Carlo need to be planted in the substrate?

Yes. Split it into small clumps and push each one into the substrate with tweezers, leaving gaps for it to fill.

Does Monte Carlo need CO2?

No, but it helps. Monte Carlo can grow without injected CO2, and added CO2 makes it grow faster.

How much light does Monte Carlo need?

Monte Carlo wants medium light. A light sold for planted tanks covers it.

Does Monte Carlo need root tabs?

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

How do you propagate Monte Carlo?

Monte Carlo 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.