Monte Carlo

Scientific name: Micranthemum tweediei 'Monte Carlo'

Origin: Argentina

Growth: medium, 3–5 cm carpet

Light and CO2: medium light; CO2 preferred, not required

Placement: foreground carpet

Propagation: runners; divide clumps

Monte Carlo (Micranthemum tweediei 'Monte Carlo') spreads sideways into a low carpet of small, round, fresh green leaves on creeping stems, reaching only 3–5 cm tall. It comes from Argentina and is the easier of the common carpeting plants: it will carpet in medium light without added CO2, though stronger light and CO2 make it tighter, faster and flatter. Once settled it sends out runners, horizontal shoots that root as they go, and joins up into a lawn over a couple of months. Plant small clumps a few centimetres apart rather than one big lump. Nursery plants are grown with their leaves in air, so a fresh pot often loses some leaves as it converts to underwater growth; the roots and stems are what matter and new leaves follow. A carpet gives shrimp a huge amount of surface to pick over, and the layer of leaves traps food and biofilm, the microbial film they graze. Trim it like mowing a lawn once it thickens so the lower layer does not rot.

Water: ordinary tropical conditions suit it; it tolerates partial shade. Tropica rates it medium difficulty mainly because it needs steady light to stay flat.

Planting: split the pot into small clumps, remove most of the rock wool, and plant each clump a couple of centimetres apart with roots buried and leaves clear. A fine substrate or root tabs (fertiliser capsules pushed into the substrate) help it establish.

Light and feeding: medium light (about 0.5 W per litre on Tropica's scale; Aquarium Co-op gives 20–50+ PAR). CO2 injection (carbon dioxide gas added to boost growth) is preferred but not required. Feed with liquid fertiliser and trim the carpet with curved scissors as it thickens.