Begonia maculata sold as ‘Polka Dot’

A trade selection with Brazilian forest origins

Plants sold as Begonia maculata ‘Polka Dot’ belong to the cultivated forms of Begonia maculata, a species from southeastern Brazil’s Atlantic Forest.

The wild species grows among warm, humid Atlantic Forest vegetation shaped by regular rainfall and light filtered through the canopy.

Care for cane-forming foliage plants

Repotting

Repot Begonia maculata when roots circle the pot or emerge below, water runs through dry channels, the canes become unstable or the mix loses its spring. Restake the plant immediately after repotting, but leave each tie loose enough for the cane to thicken.

Light

Place Begonia maculata beside a large east-facing window, or a short distance from a south or west window behind a sheer curtain. The plant develops the silver polka dots and red undersides naturally.

Watering

Water Begonia maculata when the upper layer of the substrate has dried while the centre of the root ball still feels faintly moist. On the plant, check the centre of the root ball as well as the surface.

Temperature

Cold wet roots are more vulnerable than a dry surface, so move the pot back from icy glass after watering.

Humidity and airflow

Aim for stable moderate humidity and keep the plant out of persistently damp air. Moderate indoor humidity is workable, while somewhat higher humidity can help new leaves open cleanly.

Fertilising

Feed Begonia maculata with a balanced complete houseplant fertiliser at a low dose while it is actively making leaves or shoots. Extra fertiliser will not strengthen weak canes on the plant.

Common problems with Begonia maculata sold as ‘Polka Dot’

Brown centres on silver polka dots

Normal air-space spotting is firm and stable. A water-soaked centre, yellow margin or lesion that spreads through several dots suggests leaf-spot disease. Isolate, remove affected leaves and avoid splashing the foliage. If a lesion reaches the petiole or cane, cut back to firm, healthy tissue promptly.

Long angel-wing leaves curl at the edges

A dry root ball or hot airflow can curl the broad blades. The same symptom in wet mix points to damaged roots. Feel the mix before watering and inspect the roots if it remains wet. Rehydrate a dry throughout plant, but restore aeration and remove dead roots when the mix is still wet.

Tall canes lean and become bare

Wide internodes and a lean toward the window indicate stretching. Increase bright filtered light gradually, rotate the pot and prune above a node to activate side buds. Stake loaded canes loosely. A firm bare cane can reshoot; a black or mushy one should be removed.

Red leaf undersides show dark patches

A red-purple reverse is normal. Disease or cold damage changes the texture as well as the colour: affected areas become translucent, soft or collapsed and are visible from the upper surface. Remove spreading tissue and inspect the cane if the petiole is darkening.

New leaves and flowers are streaked

Search for thrips in folded leaves and flower clusters. Their silvery rasps, black specks and distorted growth cut across the regular polka-dot pattern. Isolate the plant, remove badly damaged blooms and repeat a suitable treatment at the label interval.

Begonia maculata ‘Polka Dot’ 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.

What does Begonia maculata mean, and who first published it?

Begonia honours Michel Bégon. The epithet maculata means spotted and refers to the pale dots on the leaves.

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

Giuseppe Raddi first described Begonia maculata in 1820 in Alcune Specie Rare o Nuove di Piante Brasiliane, page 406.