Begonia subnummulariifolia

Natural range and habitat of Begonia subnummulariifolia

Begonia subnummulariifolia is native to Pulau Banggi (Banguey Island) off Borneo, where it grows in wet tropical habitat.

Care for Begonia subnummulariifolia

Give the dense mat bright filtered light. A steady 18–24 °C suits the plant; sustained temperatures below 10 °C are too cool. 50–60% humidity and gentle airflow suit this tiny creeping Begonia; a terrarium or plant cabinet can be useful if the roots still receive air.

Use a shallow container with loose mix that stays lightly moist and drains freely. Water when the surface begins to dry, then allow the excess to drain.

Use a very weak balanced fertiliser every few weeks while the creeping stems are extending.

Repot when stems reach the pot edge or compacted mix begins to drain noticeably more slowly.

Stems can root where they touch the mix, and established rooted sections can be separated. Propagate from healthy stem or rhizome sections, keeping at least one healthy growing point on each piece.

What can go wrong with Begonia subnummulariifolia

• Dark, soft areas spread along several creeping stems: Saturated potting mix can let stem or basal rot move through the dense mat. Cut affected stems back to firm, healthy tissue with a clean, disinfected tool, then discard the rotted material and old mix before rooting healthy stem tips in fresh, airy potting mix.
• Grey mould appears within the dense mat: Botrytis can grow on dead leaves and damp stems where airflow is poor. Remove affected and dead material, and keep the plant separate if mould is spreading. A drier surface and gentle airflow help limit further spread.
• Fine pale speckling develops across the tiny leaves: Mites can be difficult to see at this scale. Keep the plant separate while checking the foliage closely. If mites are present, use a product labelled for mites on indoor ornamental plants and repeat it at the label interval.
• The mat develops crisp brown sections: A shallow container can dry quickly, especially in warm moving air. If the potting mix has begun to dry, water thoroughly and let excess drain. Moving the plant away from heaters helps the lightly moist mix dry at a steadier rate.

Begonia subnummularifolia is toxic to people and pets

• Keep this plant away from children, cats and dogs.
• The roots and rhizomes contain the highest levels of soluble oxalates, and the sap can irritate skin.
• Chewing may cause mouth irritation, drooling, vomiting or stomach pain. Contact a veterinarian or medical professional if symptoms develop.

How did Begonia subnummularifolia get its name?

Begonia honours Michel Bégon. The name subnummularifolia combines sub-, somewhat or almost, with nummularifolia, coin-leaved.

Carl Linnaeus established the genus Begonia in 1753 in Species Plantarum, page 1056.

Elmer Drew Merrill first described Begonia subnummularifolia in 1926 in Philippine Journal of Science 29: 403.