Begonia rex 'Black Mambo' ('Dark Mambo')

Begonia rex ‘Black Mambo’ (‘Dark Mambo’)

Near-black rex leaves and shallow crown

Begonia rex ‘Black Mambo’ has near-black rex leaves and compact rhizomatous growth. The broad, asymmetrical leaves develop deep purple-black colour with burgundy undertones, a slight metallic sheen and a gentle spiral near the leaf base. New leaves grow from a shallow rhizome that spreads across the substrate surface, keeping the plant low and compact. Older leaves gradually age out as fresh growth appears along the rhizome. In cooler, darker months, the plant may hold fewer active leaves until warmth and light improve. A wide, low pot gives the rhizome room to spread sideways.

Begonia rex ‘Black Mambo’ features

• Dark purple-black Rex Begonia foliage
• Broad asymmetric leaves with a slight spiral form
• Compact rhizomatous crown
• Surface rhizome that spreads outward
• Wide, shallow pot suited to sideways rhizome growth

Rex Cultorum Begonias trace back to Begonia rex, a rhizomatous species native from southern Bhutan to northern Myanmar. ‘Black Mambo’, also sold as ‘Dark Mambo’, refers to this cultivar’s deep, near-black foliage.

Begonia rex ‘Black Mambo’ care

• Light: Bright filtered light; shield the leaves from strong midday sun.
• Watering: Water when the top 2 cm are lightly dry, then let excess water drain fully.
• Substrate: Use a light, porous mix with bark, perlite, pumice and an organic base.
• Pot: Use a wide, shallow container with drainage.
• Humidity: Around 50–70%; keep air moving around the leaves.
• Temperature: 18–26 °C; keep the substrate warm and well drained.
• Feeding: Use diluted fertiliser while new leaves are forming.
• Grooming: Remove older leaves at the base.
• Repotting: Refresh the mix when it compacts or when the rhizome reaches the pot edge.
• Propagation: Propagate by leaf sections or rhizome division.

Rex leaf and rhizome checks

• Crisp leaf edges: dry air, irregular moisture or salt build-up.
• Limp leaves in damp substrate: roots or rhizome may be starting to rot.
• White powdery patches: wet leaves and still air can encourage powdery mildew.
• Fine pale speckling: check for mites, especially in dry conditions.
• Fewer leaves in winter: lower light and cooler temperatures slowing growth.

New leaves may show warmer tones before darkening. Adjust light for steady growth first; the leaf colour deepens naturally with age. Rex Begonias can flower, usually with small pale blooms held above the leaves. Remove faded flower stems once they finish. During cleanup or division, keep trimmed leaves, roots and rhizome pieces away from pets and small children. Rex means king, while ‘Black Mambo’ and ‘Dark Mambo’ describe the deep foliage colour. With steady warmth, filtered light and careful watering, new dark leaves keep growing from the shallow rhizome.