begonia plant will eventually die. These evergreen perennial plants are native to the tropical rainforests in Brazil. As a cane begonia, the plant’s thick stems hold a bit of water and don’t like wet conditions. A humidifier would be the ideal way to maintain the right humidity levels around the plant. Because of their native environment, high humidity, warm temperatures, and indirect or filtered light are the essential care factors. Begonia Maculata Flowers. Because begonias get easily damaged by cold weather, you should bring your begonia inside as soon as it gets below 60 °F or 15 °C. anyway, I am very cautious now with spraying rexes. Each mature leaf can grow in the range of 20 to 25 cm in size. Leaves. However, the plant will still thrive with higher humidity levels. But B.maculata has stronger leaves then rexes, I think. A humidity level of 45% is recommended for the polka dot begonia. Start with a light commercial potting soil and add a few handfuls of perlite along with a lesser amount of wood chips until you get a springy, fluffy mix. only when they've been outside , including new nursery plants. However, the begonia maculata is prone to powdery mildew that would compromise the beauty of the plant. I don't have problems with mildew/fungal on begonias indoors (when they are kept strictly indoors and are my propagations from leaves). Clusters of angelic white flowers enhance the beauty of this peep in the warm days of spring and summer. Maculata can grow up to 60 inches or 1.5 meters in height. Also, rain is a huge problem for polka dot begonias as the dew collected on leaves can lead to mildew so if you can, place your polka dot begonia under a … Begonia maculata is a type of cane begonia that has thick stems that support spotted angel wing-shaped leaves.