Begonia masoniana ‘Tricolor’

A cultivated form with southern Chinese and Vietnamese origins

Begonia masoniana ‘Tricolor’ is a horticultural selection of Begonia masoniana, a rhizomatous species from Guangxi in southern China and northern Vietnam.

Wild plants occur in sheltered forest and limestone country, with seasonal rain, high atmospheric moisture and light filtered by nearby vegetation.

How to care for Begonia masoniana ‘Tricolor’

Light

Place Begonia masoniana ‘Tricolor’ close to an east or north-east window, or within about 1 m of a south or west window behind a light curtain. Direct sun tolerance is limited: the upper leaf surface bleaches or scars and the rhizome dries unevenly under a strong unacclimated beam. With too little usable light, petioles stretch, the mound opens and colour or surface texture becomes less clear. The markings are genetically fixed, while stronger light increases the risk of scorch. Healthy growth shows the cream banding within the green and dark leaf pattern as an inherited form of Panaschierung. More light cannot manufacture pale sectors, and excessive sun damages them first.

Watering

Water Begonia masoniana ‘Tricolor’ after the upper 2–3 cm has dried while the shallow root zone below remains faintly moist. Soak the substrate evenly, let it drain fully and never leave the inner pot standing in water. The thick rhizome holds a little water, but repeated complete dry-outs still kill the fine roots beneath it. Do not bury the rhizome in moist mix. Its feeder roots need moisture, while the rhizome itself needs an exposed, airy surface. Probe just below the rhizome of ‘Tricolor’, where the active roots are using water. Drying depends on light, temperature, airflow, how fully roots fill the pot and the container material.

Substrate and roots

Begonia masoniana ‘Tricolor’ has a thick horizontal rhizome supported by feeder roots near the top of the pot. Aim for a loose, evenly wetting blend of fine bark, coir or peat-free substrate, and pumice or perlite. Use small, resilient particles around the feeder roots; avoid both a heavy wet core and a loose bark-only medium. Give the growing rhizome open surface space without surrounding its shallow roots with an oversized container. Keep the rhizome of ‘Tricolor’ uncovered and give its growing end open surface space.

Temperature

Keep Begonia masoniana ‘Tricolor’ at 18–26 °C, with 15 °C as a cautious indoor minimum. Winter ventilation should not blow across damp roots or soft new leaves. Moderate day-to-night change is useful. Sharp temperature swings are not.

Humidity and airflow

Moderate, stable humidity supports clean growth without keeping the plant persistently wet. Aim around 50–70% if new leaves catch or crisp as they open. Keep the exposed rhizome of ‘Tricolor’ dry at the surface even when the surrounding air is moderately humid. Keep humid air moving gently so leaf bases and stem tissue can dry.

Fertilising

Feed Begonia masoniana ‘Tricolor’ with a complete foliage fertiliser at about quarter strength every five to six weeks while it is actively making leaves or shoots. A plant that is still unfolding leaves in winter still uses nutrients, while an inactive one does not. Alternate feeding with plain water so fertiliser residue does not build up around delicate feeder roots. Keep nitrogen modest. Strong feeding makes soft growth but cannot increase the cream Panaschierung.

Repotting

Repot Begonia masoniana ‘Tricolor’ when the rhizome reaches the rim, roots fill the shallow pot, water moves unevenly or the substrate has compacted. A pot 2–3 cm wider is normally enough for the next stage of growth. Lift the shallow root mass intact. Separate only a rhizome section that already has feeder roots and an active growing point. Work while the plant is actively growing in stable warmth so new roots can resume quickly. Set ‘Tricolor’ so the growing rhizome has room to advance across the fresh mix.

Support, pruning, handling and leaf care

Leave the rhizome of Begonia masoniana ‘Tricolor’ exposed as it crosses a shallow pot. A division should include roots, a live bud and enough green tissue to sustain its pale patterned leaf. Turn the pot gradually over several weeks so fresh growth can adjust without twisting. The raised surfaces across the cream, green and dark patterned leaves of Begonia masoniana ‘Tricolor’ catch dust but should not be pressed or polished. Use a soft brush between the bumps, supporting the blade from beneath. Cut fully spent leaves or flower stems cleanly at the base. Tearing can injure the crown.

Signs of stress in Begonia masoniana ‘Tricolor’

Pale or pink sectors scorch first

The cream and pink parts have less green tissue and may scorch against hot glass before the darker cross is affected. Pull the plant back from direct sun and keep useful green portions of the leaf. Remove a soft translucent patch if it continues to grow.

New leaves contain little pale colouring

Sectoring can vary between leaves and is genetic; it is not restored by direct sun or withholding nutrients. If a vigorous all-green growth point begins to dominate and preserving the tricolour form matters, prune it back to a node that previously produced mixed tissue. Otherwise the shoot is healthy and can remain.

Translucent spots on the puckered blade

Natural colour boundaries remain firm. Wet-looking or yellow-rimmed spots that enlarge across green, pink and cream tissue suggest leaf-spot disease. Isolate, remove affected leaves, keep the rough surface dry and disinfect tools. Petiole or rhizome softness demands faster intervention.

Surface rhizome darkens and yields

Softness can travel quickly beneath the low tricolour crown. Unpot it, cut away damaged tissue until the entire cross-section is firm, and set the survivor at the surface of clean airy mix. Take a healthy patterned leaf cutting at once when the variegated growing point is close to the damage.

Young variegated leaves open twisted

One damaged leaf after handling may be physical damage. Several tight, bronzed or scarred new leaves need a close check for broad mites and thrips. Isolate the plant, identify the likely pest and test any contact treatment on one leaf because pale sectors may show chemical marks.

Is Begonia masoniana ‘Tricolor’ toxic to cats and dogs?

Begonia masoniana ‘Tricolor’, including its broad, puckered blades, contains soluble calcium oxalates and is toxic to cats and dogs. A pet that chews the leaves or a stem may drool or vomit; underground portions contain the strongest concentration. Keep the pot beyond a pet’s reach. Collect removed leaves and block access to exposed roots or crown pieces during repotting. Recheck access after moving furniture or placing the pot on a lower surface. If drooling, vomiting or swallowing follows contact with the leaves or a stem, contact a veterinarian. Bag discarded roots, spent substrate and cuttings after repotting, then wash hands.

Three colours in a Mason begonia

‘Tricolor’ means three-coloured and describes a form whose leaves combine three conspicuous colour zones or tones. ‘Tricolor’ is the cultivar name of this Begonia masoniana selection.

The epithet masoniana honours Maurice L. Mason. The accepted name Begonia masoniana Irmsch. ex Ziesenh. was validly published in The Begonian in 1971.