Begonia masoniana ‘Rock’

The wild setting of Begonia masoniana

Begonia masoniana ‘Rock’ is a horticultural selection of Begonia masoniana, a species native to Guangxi in southern China and northern Vietnam.

The species grows in sheltered forest and limestone environments, where seasonal rainfall, warm humid air and filtered light shape its habitat. Rooting surfaces differ among sites.

Leaf and rhizome care for foliage plants

Support, pruning, handling and leaf care

Begonia masoniana ‘Rock’ needs no stake and stays tidiest when its short rhizome is guided around a low pot. Wait until an ageing leaf is fully yellow, then cut it at the base.

Light

A practical home position for Begonia masoniana ‘Rock’ is close to an east or north-east window, or close to a south or west window behind a light curtain. Acclimate it gradually, since sudden intense exposure means the upper leaf surface bleaches or scars and the rhizome dries unevenly.

Watering

water Begonia masoniana ‘Rock’ after the upper layer of the substrate has dried while the shallow root zone below remains faintly moist. A rhizome held against wet compost can deteriorate before the leaves react.

Humidity and airflow

Begonia masoniana ‘Rock’ grows best when humidity stays steady. Pair moderate humidity around the plant with enough air movement to dry the crown after cleaning.

Fertilising

Feed Begonia masoniana ‘Rock’ lightly while the rhizome is extending and new leaves are forming. Apply fertiliser to an already moist root ball and avoid concentrated salts around the fine roots.

Repotting

Give Begonia masoniana ‘Rock’ fresh mix once the rhizome reaches the rim, roots fill the shallow pot, water moves unevenly or the substrate has compacted. Set the plant so the growing rhizome has room to advance across the fresh mix.

Begonia masoniana ‘Rock’: problems and solutions

Compact quilted leaves wilt together

The small clump may dry quickly at the surface but remain wet underneath. Check the entire root ball: water a genuinely light pot, but unpot a heavy one that stays limp. Trim brown soft roots and reduce excess potting volume so the compact rhizome is not surrounded by stagnant mix.

Brown pits on rugged leaves

Dry, sharply bounded pits can follow sun or spray damage. Soft pits that expand through the quilted tissue are signs of decay. Keep the leaf surface dry, remove spreading lesions and improve airflow through the compact crown. Clear dead leaf pieces from around the rhizome.

Iron Cross marking looks black

Use texture and any change in size as the guide. The cultivar’s central mark can be very dark and firm. Damage appears as irregular wet or soft tissue spreading beyond the normal veins. Mark the edge of the area and check it again. Isolate the plant if the spot expands or softens.

Short rhizome rots from one end

Cut the affected end back in small stages until the inside is clean, firm and healthy. Disinfect the blade between cuts and reroot the surviving portion shallowly. If decay has reached the centre, take a healthy leaf cutting immediately.

Hardened and uneven new leaves

Inspect within the compact crown for broad mites and thrips. Broad mites produce brittle bronzed distortion; thrips leave irregular pale scarring and black specks. Isolate the plant and apply the chosen treatment around hidden petiole bases. Keep the rhizome from becoming saturated.

Begonia masoniana ‘Rock’ 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 masoniana get its name?

Begonia honours Michel Bégon. The epithet masoniana honours the British plantsman Maurice Mason.

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

Rudolf Christian Ziesenhenne first described Begonia masoniana in 1971 in Begonian, volume 38, page 52; Edgar Irmscher had proposed the name.