Begonia ‘Corallina de Lucerna’

An heirloom cane Begonia from the 1890s

Begonia ‘Corallina de Lucerna’ is an old horticultural cane cultivar known since the 1890s and also circulated as ‘Lucerna’ or ‘Lucerne’.

Cane Begonia breeding is closely connected with tropical American species. Many grow in warm, humid forests with regular rainfall and light filtered through surrounding vegetation.

Indoor care for Begonia ‘Corallina de Lucerna’

Light

A practical home position for Begonia ‘Corallina de Lucerna’ is beside a large east-facing window, or 0.5–1.5 m back from a south or west window behind a sheer curtain. A little early-morning or late-afternoon sun is useful after acclimation. Hot midday rays through glass can scorch the thin blades. A position several metres from a window is too dark when the canes lengthen between nodes, lean towards the window and carry smaller, duller new leaves. The plant develops the silver spotting on the olive blades naturally. Useful light keeps new growth compact and the colour clear, but direct sun cannot intensify an inherited pattern. Suitable light produces sturdy, normally proportioned new growth with the expected colour.

Watering

Let the upper layer change first, then water Begonia ‘Corallina de Lucerna’ when the upper 2–3 cm has dried while the centre of the root ball still feels faintly moist. Water from several points across the surface, continue to runoff and discard the collected water. A root ball that stays wet loses oxygen around the fine roots and may soften the lowest part of a cane. A brief surface dry phase is useful, but letting the whole root ball dry can cost fine roots and lower leaves. On ‘Corallina de Lucerna’, check the centre of the root ball as well as the surface. Tall canes can hide a core that is still damp. Light, temperature, leaf area, pot size and pot material all change how quickly the mix dries.

Substrate and roots

Plan the potting mix around fine, easily torn roots below the cane bases. Choose a moisture-holding but freely draining houseplant mix containing small bark and perlite or pumice. Avoid fine mix that packs into a wet core beneath the upright stems. Give the canes physical stability with pot weight or a stake; an oversized root ball remains wet for too long. Use only enough extra pot depth to stabilise ‘Corallina de Lucerna’; unused wet mix remains saturated for too long.

Temperature

Warm, even conditions suit Begonia ‘Corallina de Lucerna’: roughly 18–27 °C, staying above 14 °C. A cold sill can chill the shallow roots before the room thermometer shows a problem. Hot dry airflow damages soft growth and makes the upper mix dry faster than the roots below.

Humidity and airflow

Begonia ‘Corallina de Lucerna’ grows best when humidity stays steady. Aim for stable moderate humidity and keep the plant out of persistently damp air. Around 45–60% is workable and 55–70% is useful while new leaves open. Clean, full-sized new leaves on ‘Corallina de Lucerna’ indicate that humidity is sufficient. A quiet fan outside an enclosure or normal room circulation is enough. The leaves should not flutter constantly.

Fertilising

Match feeding to visible growth in Begonia ‘Corallina de Lucerna’: use a balanced complete houseplant fertiliser at quarter to half strength every three to five weeks. Continue lightly at any time of year if growth remains steady. Pause when cool conditions stop it. If leaf growth slows while salts collect at the pot rim, flush first and resume at a weaker concentration. Extra fertiliser will not strengthen weak canes on ‘Corallina de Lucerna’. Useful light must support the growth first.

Repotting

Give Begonia ‘Corallina de Lucerna’ fresh mix once roots circle the pot or emerge below, water runs through dry channels, the canes become unstable or the mix loses its spring. The next pot should be roughly 2–4 cm wider and retain the same basic shape. Move the central root ball intact. The fine roots tear easily and should not be washed bare. Choose a period when roots and leaves are growing, and avoid severe root work in a cold, wet room. Restake ‘Corallina de Lucerna’ immediately after repotting, but leave each tie loose enough for the cane to thicken.

Support, pruning, handling and leaf care

Stake the strong upright canes of Begonia ‘Corallina de Lucerna’ before its silver-spotted canopy becomes heavy. Prune one cane at a time just above a node to preserve height while encouraging fresh side growth. If one side faces the window, rotate by small steps only after the newest leaf has hardened. Hold each petiole steady when cleaning a mature leaf of Begonia ‘Corallina de Lucerna’. A soft damp cloth is suitable, but new unfolding leaves should be left untouched. Prune dead tissue back to a healthy base, taking care not to nick the next bud or leaf.

Begonia ‘Corallina de Lucerna’: problems and solutions

Silver dots are joined by translucent spots

The regular silver spotting is fixed, dry and repeated across the leaf. A new glassy mark, yellow rim or expanding brown area is damage. Remove the affected leaf if it continues to spread, keep irrigation off the canopy and watch the cane for a dark soft streak.

Tall canes become bare and lean

Older lower leaves are eventually shed, but very wide gaps and a strong lean point to one-sided or inadequate filtered light. Turn the plant regularly and support canes carrying heavy foliage. During active growth, shorten an overlong stem just above a node. The healthy top can be rooted separately.

Large flower clusters pull a cane over

The hanging pink blooms can outweigh a soft new cane even when the stem is healthy. Tie the cane loosely before it bends or shorten a poorly placed branch after flowering. A clean crease is mechanical; a wet dark break should be cut back to solid cane.

Flower clusters turn brown and mouldy

Spent petals can remain caught among the spotted leaves and cane joints. Remove fading clusters, clear fallen flowers and improve gentle airflow. Grey fuzz confined to dead petals is easily removed; softness spreading into the flower stalk or cane needs faster pruning to firm tissue.

Can cats or dogs chew ‘Corallina de Lucerna’?

‘Corallina de Lucerna’, including its long olive-green angel-wing leaves, contains soluble calcium oxalates and is toxic to cats and dogs. A pet that chews the leaves or a stem may drool or vomit; the concentration is greatest in roots and related underground tissues. Collect pruned stems and fallen leaves from below the upright canopy. Block access to the open root ball and every cane cutting during repotting. Choose a position where fallen leaves cannot land within a pet’s reach as the upright stems gain height. 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.

A cane begonia from Lucerne

‘Corallina de Lucerna’, also shortened to ‘Lucerna’, is an old cane begonia associated with the Swiss city of Lucerne. It is generally credited to Wettstein and dated to about 1892, although published accounts disagree about its exact parentage.

‘Corallina’ means coral-like and refers to the coral-red colour associated with this line. The cultivar later became important in the breeding of Superba-type cane begonias.