Splashy and spectacular, Begonia maculata, or the Polka Dot Plant, as it is commonly called, is a glorious addition to the houseplant collection. Featuring deep green leaves flecked with silver polka dots, the whimsical Polka Dot Plant is as fuss-free as it is beautiful.
Origin and History of Begonia Maculata
The aptly named Begonia maculata is called the Polka Dot Plant due to the profusion of silver spots on the leaves. Begonia maculata is native to the rainforests of Brazil, but now it is also found growing naturally in Argentina, Mexico, and Cuba as an introduced species.
Begonias have been popular houseplants for centuries, but Begonia maculata is a relatively new species in that regard. It was first described to science in 1820 by an Italian botanist. “Macula” means spotted and is a reference to the speckled foliage.
Begonia Maculata Care
In this section we’ll cover everything you need to know about Begonia maculata care.
Growth Habit
Polka Dot Plant leaves start out light yellow or olive green, then mature to dark, deep emerald green. The leaf undersides are a vivid maroon which contrasts fantastically with the dark green tops. This houseplant will grow up to 5 feet tall, given the space and proper care. Mature leaves average 5-7 inches long.
Begonia maculata stems are thick, woody, and knotty. These houseplants are fast growers, too. Expect to see many new leaves in just a few months during the growing season.
A Polka Dot Plant allowed to grow to its full height will need support. Stakes, poles, and non-harmful plant ties work great. Don’t put ties close to leaves or flower stems as they are fragile and may break.
Water
Begonias like moist soil that isn’t overly wet or soggy. It should never dry out completely, either. This may seem like a tricky balance to maintain, but it just means you need to be aware and check the plant semi-frequently – at least once a week.
The way to be sure you’re giving your Polka Dot Plant proper watering is to check the soil every time before you water it. Stick your finger in the top 1-inch of soil. If it is still damp, hold off on watering for a little while longer. This will prevent overwatering, which is also a potential issue and leads to root rot.
When you’re watering, be careful not to get the Begonia’s leaves wet. Wet leaves lead to the development of fungal diseases and encourage pests. A watering can with a long spout may be necessary if you’re got a particularly large Begonia.
Never let the roots sit in water for an extended period, as this leads to root rot. If you’ve got a saucer underneath your pot, empty it out 10-15 minutes after watering to give the soil time to drain.
Light
Bright, indirect light is the best. Don’t let the plant sit in direct sunlight, as this can burn the leaves. Polka Dot Plants will be okay in semi-low-light locations, but growth, including leaf size, will be significantly diminished. If the light is too low, the leaves will start to lose color, eventually turn yellow, and then fall off.
Temperature & Humidity
Being a tropical plant, Begonia maculata appreciates heat and tons of humidity. Average household temperatures, between 55-85F, are the best, as well as a humidity level above 50%.
Pay attention to the inside location as the seasons change. Heat registers, air conditioners, window drafts, and open or drafty doors all have an impact on humidity, heat, soil temperature, and soil moisture. A Begonia placed near a heat register will dry out (soil and plant) much quicker.
To increase the humidity in your home, consider purchasing a humidifier. Or, you can set up a DIY humidity tray. Simply fill a metal tray with water and pebbles. Place the Begonia on top of the stones and fill the tray with water. As the water evaporates, humidity increases. You’ll need to refill the tray every couple of weeks with water to keep it working.
The DIY humidity tray may be enough for your Begonia, but if you see browning leaf tips, it likely needs an actual humidifier. Investing in a hydrometer to test the humidity levels in your home is a good idea, especially if you have a lot of humidity-loving tropical houseplants.
Soil
An all-around high-quality potting mix is sufficient for the Polka Dot Plant. To improve water retention and drainage, add some coco coir and perlite to the mix. The perlite assists in water absorption while the coco coir ensures that any excess water drains well and that air is able to circulate around the roots.
Fertilizer
During the growing seasons (spring and summer), add a balanced houseplant fertilizer mixed at half strength once a month. Hold off adding fertilizer in the winter when the Polka Dot Plant is resting.
Repotting
Begonia maculata prefers being a bit rootbound, so don’t worry about moving it to a larger pot unless you want the plant to grow bigger. It should be repotted every year, though, to replace and refresh the potting soil. Potting soil provides essential nutrients to a houseplant, and it gets used up and needs replenishing.
A common problem Polka Dot Plants have is exhausted or too dense soil. If you’ve recently acquired your Begonia, or if you haven’t repotted it since getting it, you definitely should. Poor soil quality is the leading cause of stunted growth. Take the root ball out of the soil and examine it for rot, cutting off any you see and repot in fresh potting soil.
Repot your Polka Dot Plant in the spring, at the beginning of the growing season. Always be sure to use a pot with drainage holes. If you’re going to repot to a larger container size, choose one that is just one size larger. This promotes even strong growth.
Pruning
Remove any unhealthy or dead leaves as they appear (some will be a regular part of growth). Many Begonia owners want to encourage bushier, denser development since this houseplant can grow quite large. Luckily, this is a plant that isn’t harmed by trimming, pruning, or cutting back.
And, it does take some consistent pruning to create a bushy look; the Polka Dot Plant naturally tends to get leggy with sparse leaves. Often, when allowed to grow to its full 5-foot length, it is long and stemmy with big leaves interspersed along the central cane.
When you cut back the canes, new leaves form at the base of each cane, creating a denser appearance. It’s fine to cut Begonia maculata stems back up to two-thirds. Do the big prunings in the spring or summer, when the Polka Dot Plant is actively growing. To keep this fast-growing houseplant to a specific size, you’ll need to prune it at least once a year and possibly twice.
Toxicity
Begonia maculata is toxic to people and animals. Keep your Polka Dot Plant away from children and pets.
Begonia maculata Propagation
There are two possibilities for propagating Begonia maculata. Both are easy, so it’s up to your personal preference.
Water Propagation
- Clean and sterilize a pair of sharp scissors.
- Choose a healthy stem to cut. It should have at least one node (the junction where stem and leaf meet) and one leaf.
- Cut below the node.
- Place the cutting in a narrow jar of water (this is so the leaf doesn’t fall in). The node must be all the way in the water.
- Put the jar in a location with bright, indirect light.
- Once a week, change out the water and top of the water, as needed.
- In 2-4 weeks, roots will form at the node.
- When the roots reach 2-3 inches long, they are big enough to be potted in soil.
Soil Propagation
- Follow the first three steps from the water propagation method listed above.
- Stick the cutting into a small pot with moistened potting mix.
- Place the pot in a location with bright, indirect light.
- Put a plastic bag over the top of the pot to retain humidity. Lightly tuck the bag around the pot, leaving one side partially open to ensure good airflow.
- Keep the soil evenly moist for the next 3-4 weeks.
- After a few weeks, check that roots are forming. Do this by very lightly tugging at the stem to see if there is resistance.
Pests & Disease
In this section we’ll cover pests and other common issues with Begonia maculata.
Powdery Mildew
A disease caused by leaves getting wet and remaining wet too long, powdery mildew is a common houseplant issue. To prevent this from happening, avoid getting the leaves wet. A long-spouted watering can will make this easier. Powdery mildew is best treated with a fungicide to kill the spores and removal of the affected leaves.
Powdery mildew can be difficult to treat fully, so it’s best to focus on prevention. Allowing leaves and soil to dry out, as well as maintaining good airflow around the plant, will go a long way in preventing powdery mildew. Watering in the morning is best because it allows time for the leaves to dry if they do get wet.
Mealybugs, Thrips, Whiteflies, Spider Mites, and Aphids
These insects are all small and difficult to see until they’ve caused considerable trouble. Thankfully, though, there are good treatments for getting rid of them. The key is to catch the situation as early as possible through frequent, systematic investigation of the plant, including looking under the leaves.
The other vital part of treatment is to be consistent; continue treating for a while even after you don’t see any signs of pests. Larvae or eggs may be hiding in the soil or leaf undersides, waiting for it to be safe to come out.
Use a neem oil spray to treat these bug infestations. Mix 2 teaspoons neem oil with 1 teaspoon dish soap in a quart spray bottle. Fill the rest of the bottle with water and shake well. Spray the entire plant, leaf tops and undersides, stems, and soil. Do this in the morning, so the leaves have time to dry. Repeat the application of neem oil spray every 4-7 days.
Common Questions and FAQs
Here are a few common questions we get about keeping Begonia maculata:
Will my Polka Dot Plant flower?
Yes, it is definitely possible that your Polka Dot Plant will flower, given the proper care. The flowers are small and white and will appear during the growing season. Using fertilizer increases the chances of the Begonia blooming; the extra nutrients are needed to produce flowers.
How tall will my Begonia maculata get?
If you give it space and care, it will grow unchecked. The average height for a Polka Dot plant is between 3-5 feet tall. A trellis or stakes will be necessary for support if it gets this large. Read the section on pruning to learn how to keep this Begonia smaller.
What causes crispy, brown leaves?
Lack of water and humidity will cause the leaves to brown and turn brittle. If you notice this, reassess the watering schedule and amount of moisture in the room.
Why are the leaves of my Begonia maculata yellow?
Yellow leaves are caused by overwatering. Don’t forget to check the soil every single time before watering. The top inch of soil should be dry.
Leaves start fading in color and eventually turn yellow when the plant isn’t receiving enough light. This will look different from yellow leaves caused by overwatering. You’ll notice first that the green coloring fades, turning a light green before turning completely yellow and falling off.
Why is my Polka Dot Plant leggy?
Legginess is a common problem caused by insufficient light. Your Polka Dot Plant is stretching out its stems as far as possible to reach the light before growing new leaves. This will not cease until you move it to a location where it doesn’t have to extend so far itself to get light.
Some legginess is to be expected with this Begonia since it is a cane-type, which in the wild grows quite long. Pruning limits some of the natural legginess to create a bushier growth.
With its whimsical polka dots and brilliant contrasting colors, Begonia maculata is a star among houseplants. Be sure to locate it somewhere where you can easily delight in its unique coloring and rapid growth. The Polka Dot Plant likes to be center stage! Fuss-free and fast-growing, Begonia maculata will grace your household for years, even decades, with the proper care.
