Begonia thiemei

Begonia thiemei is a Vietnamese species belonging to the cane or rhizomatous begonia group, grown primarily for its striking foliar display. The leaf upper surface exhibits a strong iridescent sheen — shifting between blue-green and teal under different viewing angles — caused by the same structural colouration mechanism found in Begonia pavonina. It is a plant for dedicated terrarium and paludarium keepers who can maintain the very high humidity (above 80%) and stable warm temperatures this species demands.

In a suitable enclosed terrarium or paludarium, B. thiemei rewards patience with a slowly expanding clump of breathtaking foliage. It should be planted in a well-draining, humus-rich mix and kept away from draughts or temperature swings. Flowers are modest white to pale pink blooms, produced periodically but taking second place to the extraordinary leaves.

Light: Low to medium indirect; 500–1,500 lux; stronger light diminishes iridescence and risks leaf scorch. CO2/Humidity: No CO2; humidity above 80% critical; enclosed terrarium environment is ideal. Fertilisation: Very dilute balanced fertiliser monthly; over-fertilisation causes lush but poorly coloured growth. Placement: Plant in rich, well-draining, humus-based substrate in the shaded land area of the paludarium. Propagation: Leaf or stem cuttings placed on moist sphagnum moss in high humidity; rhizome division of mature clumps.