Begonia pavonina (Peacock Begonia)

Begonia pavonina is one of the most scientifically fascinating plants in the hobby, producing structural colour in its chloroplasts (iridoplasts) that causes the upper leaf surface to shimmer in brilliant electric blue under low-light conditions. This is an adaptive trait — the iridoplasts reflect high-energy blue light while maximising green wavelength absorption for photosynthesis in the deep shade of its Malaysian cloud-forest habitat. The result is a plant that appears to glow blue in dim terrarium lighting.

Cultivation requires careful attention to both temperature and humidity: B. pavonina is a cloud-forest species that does best below 24 °C with humidity consistently above 80%. It grows as a compact rhizomatous plant, producing modest pink flowers that are entirely secondary to the extraordinary foliage. It is best suited to enclosed high-humidity terrariums or the most sheltered areas of a paludarium.

Light: Low indirect; 300–1,000 lux; iridescence is most intense under dim light — paradoxically reduces with too much light. CO2/Humidity: No CO2; humidity consistently above 80%; cool temperatures (below 24 °C) are important. Fertilisation: Extremely dilute balanced fertiliser monthly; this species is sensitive to over-fertilisation. Placement: Plant in moisture-retentive, well-draining substrate in the most shaded, humid section of the paludarium. Propagation: Rhizome division or stem cuttings in moist sphagnum under warm humid conditions.