Cabomba

Cabomba aquatica is the fine-leaved stem plant whose fans of feathery leaves sit at the end of each stem, and it is the soft-water member of a genus that also includes the hardier Cabomba caroliniana. The leaves are densely divided and spread like a hand-held fan, giving a background a texture that few other stem plants match.

It is native to northern South America, from Colombia and Venezuela through Guyana into Brazil, where it grows in slow, soft, slightly acidic water. The stems are soft and break easily when handled, and each piece that breaks off will root and start a new plant, which makes propagation as simple as replanting trimmings.

It prefers soft water at a pH of 5 to 7 and temperatures of 23 to 27 °C, and it is considered demanding: CO₂ and steady nutrients keep the fans dense, while without them the lower stems go bare and the growth thins. Moderate to strong light suits it, and it does not grow emersed.

Plan around the plant's softness rather than against it. Plant it at the back where the stems can grow tall, and keep the water movement gentle so the brittle fans are not constantly bent by the flow. It sheds older lower leaves when light or nutrients drop, and regular trimming with the tops replanted keeps a young, dense clump, which is how the species is best maintained long term.