Featuring deep olive-green leaves peppered with silver polka dots, Begonia maculata looks a bit like a Dr. Seuss drawing come to life. Besides its official scientific name, this striking plant is also known by the common name spotted begonia. You might also hear it called the polka dot begonia or even the trout begonia. As if its spots weren’t interesting enough, Begonia maculata‘s leaf undersides are an arresting burgundy color as well. In this article, I’ll share growing and care information for this unique begonia.
Because this fancy foliage grows out from long bamboo-like stems, the polka dot begonia is classified as part of the so-called cane begonias. (Begonias that grow via canes are most closely related to wax begonias; however, they’re not the same.)
Given the right conditions, Begonia maculata is a fairly fast grower that you can bring outside during summer and keep inside during the winter months. Of course, if you prefer, you can instead grow spotted begonias as indoor houseplants year-round.
Meet Begonia maculata – The Polka Dot Begonia
There’s some confusion around the origin of the polka dot begonia—not to mention which of the many commercially available begonias can be counted among Begonia maculata.
First, here’s the real story on the European discovery and popularization of begonia plants in general and Begonia maculata, specifically. While a Frenchman named Charles Plumier popularized the name “Begonia,” it was the Italian botanist Giuseppe Raddi who would later describe Begonia maculata, in particular.
Plumier visited the West Indies during the late 1690s. While there, the botanist journaled about the area’s unusual plants and he took some samples home. Eventually, he’d name these “Begonia” to honor Michel Bégon, a fellow plant enthusiast and governor of the French West Indies.
Much later, Raddi would describe several specific begonias he saw during his own travels to the tropical forests of Brazil. One was the cane begonia, Begonia maculata. Roughly translated, Raddi’s original notes about Begonia maculata read: “A tree-like plant with unequally broad, kidney-shaped leaves. [The leaves have] well-defined, white spots.”
It’s those sharp, silvery-white polka dots that make Begonia maculata one of the prettiest begonia plants around. Still, the confusion around this striking plant doesn’t stop with early botanists’ explorations.
Look-alike angel wing begonias
Sporting symmetrical angel wing leaves, spotted “angel wing” hybrids are easy to mistake for the true Begonia maculata plant. Typically, angel wing begonias are crosses of other begonia types which can result in foliage of different colors—most often lighter green leaves with smaller, paler, more uniform dots—and different growth habits. Meanwhile, Begonia maculata has darker, asymmetrical leaves with large, bright spots, and, under optimal conditions, it can grow much taller than angel wing begonias. Dragon wing begonias also have a similar leaf shape, but lack the spots.
The best light for Begonia maculata
Imagine the bright indirect light that Begonia maculata gets in the Brazilian tropics. Those are the light requirements you’ll need to be able to mimic. That means positioning your plants out of direct sunlight since too much direct light can fade leaf color or, worse, scorch leaves altogether. If possible, find a bright spot near east- or west-facing windows, and save any Southern exposure for wintertime.
Ideal temperature and humidity levels
Begonia maculata thrives in temperatures between 65 and 80 degrees F (18.3 to 26.6 degrees C) and up to 75 percent humidity. Providing that much warmth and such high humidity indoors can be especially tricky during winter. If your bathroom has sufficiently high humidity levels—and affords enough light—try putting plants here. If need be, you can also use a plant humidifier to create a more humid environment.
Watering a polka dot begonia
Your Begonia maculata will perform best in moist soil, but you should be careful not to overwater. To determine when to water, feel the the top couple of inches of your plant’s potting soil. If the soil feels dry, it’s time. (Incidentally, you may find that you need to water plants kept outdoors for the summer much more frequently than any begonias you’re keeping inside.)
To help safeguard against water-borne fungal disease, it’s best to keep your plant’s leaves dry by watering from the bottom of the plant rather than from the top. For bottom watering, simply add a bit of water to a clean, shallow saucer and then place your plant’s pot down in it. The growing medium and your plant’s roots will slowly take up moisture as needed.
Should you prune Begonia maculata?
Yes! You should get into the habit of pruning your Begonia maculata plant at least once a year. The best time for this is late autumn. When pruning, aim to cut a couple of inches off of stems just above the plant’s nodes. This encourages bushier plant growth overall. (Additionally, it’s a good idea to trim off any dead or diseased leaves you may notice during the rest of the year, too.)
It doesn’t hurt to add an organic, slow-release fertilizer during the months when your polka dot begonia is actively growing. For best results, choose a fertilizer with a well-balanced ratio between nitrogen, phosphorus, and potassium. The nitrogen will help to boost green, leafy growth. The phosphorus and potassium will add oomph to your plant’s blooms, stems, and overall health.
Do polka dot begonias flower?
Under the right growing conditions, the spotted begonia will put on diminutive white flowers. If yours isn’t flowering, you probably need to provide it with higher light levels. Too little light, as well as low humidity levels and too much nitrogen, are the most common reasons for bloom failure in polka dot begonias.
Repotting advice for Begonia maculata
Choosing both the right pot and pot size is job one when repotting spotted begonias. Because soggy soil is a non-starter, opt for small pots with plenty of drainage holes. (Rather than picking a pot that’s much bigger than your plant’s current container, going with something that’s just slightly larger instead will make gauging soil moisture levels much easier.)
As for the potting soil itself? You can either add fresh soil mix made for tropical plants or mix one of your own. To go that route, combine two parts sterile potting mix with one part perlite and one part coco coir. (While the coco coir helps to conserve moisture, the perlite allows for improved drainage and aeration.)
Growing polka dot begonia outdoors
In the lush tropics, Begonia maculata plants are technically evergreen perennials. Still, during the warm season, it is possible to grow your spotted begonia outdoors as long as temperatures are at least 65 degrees F (18.3 degrees C). If you want to include polka dot begonias in an outdoor garden bed, you’ll likely need to amend the dirt with lots of organic matter. This is especially important if your topsoil contains heavy clay since spotted begonias simply will not tolerate overly wet conditions. To grow robust polka dot begonias outdoors, make sure the garden bed is well-draining, loamy, and slightly acidic. They look beautiful in combination with other fancy-leaved begonias, such as Begonia ‘Escargot’ and Begonia ‘Gryphon’.
And, while Begonia maculata isn’t exactly a heavy shade plant, it can get too much direct light when grown in the wrong spot outdoors. Provide these plants with bright, indirect, filtered light.
How to propagate Begonia maculata
Want to share starts of your polka dot begonia with a few lucky friends or family members? You can use soil propagation or water propagation methods to generate a whole new plant—or several! To root a stem cutting in soil or water, start by finding a healthy-looking plant section to cut. Each of your stem cuttings should include at least two or three leaves above one intact, healthy node. (Cut about one-quarter of an inch below the node itself.)
For soil propagation, fill a small pot with moistened, sterile potting mix. Slide your stem cuttings into the potting mix and press firmly into place. This will ensure the rooting zones of your new stems will make good contact with the growing medium. Keep the growing medium moist but not water-logged.
Pro-tips: To increase the likelihood of successful rooting, apply rooting hormone to the the cut end of each stem cutting before you slide them into the potting mix. You can further speed rooting by placing your pot on a seedling heat mat.
For water propagation, rainwater or distilled water work best. Simply place the cut end of your stem cuttings in a small jar or plant propagation station. Make sure the plant node remains below the water line and the leaves on your stem cutting remain above it. Plan to change out the water every week or two. You may also need to top off the water level periodically as you wait for roots to grow. Finally, you’ll need some degree of patience, too, as it can take several weeks for plant roots to develop.
Potential problems and pests
- Toxicity—If ingested, Begonia maculata is toxic to people and pets, so keep Fluffy, Fido, and other family members out of harm’s way.
- Light—Polka dot begonias grown in lower light situations are less likely to flower. Eventually, they may even drop their leaves. Rather than low light or, conversely, full, direct sunlight, these plants require bright, indirect light.
- Moisture—Outdoors, drought conditions can cause the burgundy undersides of your plants’ leaves to fade. Indoors, you might see similar fading if your plants are allowed to dry out too much. On the other hand, overwatering can contribute to root rot. This can also cause polka dot begonias to drop leaves.
- Pathogens—Spotted begonias are susceptible to Botrytis blight, powdery mildew, bacterial leaf spot, and more. If you notice areas of grayish mold or any ashy white spots forming on leaves, stems, or flower buds, you’re either dealing with Botrytis or powdery mildew, respectively. Both can develop in high-humidity environments that are too cool and dark. The fix? Remove and discard the affected portions of your plants, treat with organic fungicide as needed, and move plants to a warmer, brighter location with better airflow.
Plants with bacterial leaf spot will develop yellow spots on any infected foliage. If allowed to progress, these spots turn black and entire leaves drop off. Again, remove and discard the affected portions of your plants. To curb bacterial leaf spot, improve air circulation around your plants and avoid splashing water on plant leaves.
- Pests—Aphids, whiteflies, and mealybugs are some of the most common insects you might find on Begonia maculata. Frequently check leaf tops and undersides for signs of these insects, their eggs, and any sticky honeydew they may leave behind. Hand-picking may take care of very light infestations. Otherwise, consider applying an insecticidal soap.
Armed with these basic Begonia maculata care pointers along with more advanced repotting and plant propagation tips, you’ll be well-prepared to welcome polka dot begonias into your plant collection. Remember, bright, indirect light and high temperatures and humidity are best for Begonia maculata. Well-aerated soil is also paramount for strong growth.
Depending on your location, you may be able to keep these tropical beauties outside during the active growing season. Just make sure they don’t get too much sun where you’ve put them. You’ll also want to regularly monitor for pests and you might want to add some stakes to support your plant’s thick stems.
For more unique begonias and other plants for shade, visit these articles:
- Meet Begonia gryphon
- Begonia escargot – The snail begonia
- Shade-loving flowering perennial
- Japanese painted ferns
- Shade container gardening ideas
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