Iron Cross Begonia Guide: How to Grow & Care for “Begonia masoniana”

Complete guide to Iron Cross Begonia for everything you will ever need to know! Tips for planting and caring for “Begonia masoniana”
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The iron cross begonia may be one of the most interesting and unique-looking plants that you can get. It gets its name because of the reddish brown cross-like patterns that marks the center of its fuzzy, bright green leaves.

This plant, also known as Begonia masoniana, is a species of plant from the Begoniaceae family, native to southern China, northern Vietnam, and India. This plant greatly enjoys warm temperatures and high humidity, and can grow all throughout the year in such environments. The iron cross begonia is one of the many plants that have been given the Award for Garden Merit of the Royal Horticultural Society.

Don’t be intimidated. Fortunately, this plant isn’t as hard to care for as it is visually intriguing. It is quite easy to grow and maintain, which adds to its appeal to both amateur and experienced gardeners.

About the Iron Cross Begonia

  • The plant is named after its dark burgundy spots at the center of its foliage that resemble the German Iron Cross.
  • Aside from the unique burgundy marking, the Iron Cross Begonia’s leaves are also large in size, growing up to 8 inches (20cm) long.
  • Being from the genus Begonia, the plant has rhizomatous roots that store water
  • It was given the Award of Garden Merit by the Royal Horticultural Society.

Iron Cross Begonia Features: An Overview

The Iron Cross Begonia is an evergreen, rhizomatous perennial plant native to the tropics of Asia that can grow up to 1ft (30cm).

  • These plants stand out due to their large, bright green, pebbly oval leaves with a striking burgundy cross at the center.
  • Aside from the impressive foliage, these plants also bloom pink and white flowers during the summer.
  • This plant loves being in the shade and can grow indoors under artificial fluorescent lighting thus making it a wonderful houseplant. It is a great decorative plant, best combined with other shade-loving bright-colored plants.
  • The Iron Cross Begonia is typically sold as a potted plant. When planting Iron Cross Begonias outdoors, make sure there is enough protection from wind and frost. It is best to plant Iron Cross Begonias outdoors during warm seasons to help it grow and harder to survive the winter.
Iron Cross Begonia
Iron Cross Begonia

Growing Iron Cross Begonia

Growing an Iron Cross Begonia is a piece of cake as long as you follow some of its growth requirements. These plants prefer an organic-rich, acidic soil with pH levels between 6.1 and 6.5.

However, they can still also grow in neutral soil with pH levels between 6.6 and 7.5. African Violet potting mixes are ideal but you can also create your own organic-rich soil by mixing in a large amount of peat moss and leaf mold to the soil you already have lying around.

The soil also needs to be porous and have excellent drainage. Adding perlite or vermiculite to the soil mix can improve drainage. If these are not available, you can opt to place the Iron Cross on a raised bed. The soil should be fertilized once a month with a 10-10-5 water-soluble, high-nitrogen fertilizer diluted to half-strength. Fertilizing is best done when the soil is already moist to avoid fertilizer burn.

When it comes to sunlight, the Iron Cross Begonia needs to be kept in bright, indirect sunlight for most of the day. Avoid exposing these to direct sunlight as they will dry out and perish. Indoors, it is best to place these plants by the south, east, or west-facing windows.

Begonia masoniana
Begonia masoniana

One great thing about begonias is that they can also be grown well even with artificial lighting. You can use fluorescent grow lights on these plants for about 14 hours a day which is equivalent to 8 hours of daylight.

Being a tropical plant, Iron Cross Begonias grow well at normal room temperature or at about 65-75°F (18-24°C). These plants cannot handle temperatures of 55°F (13°C) and below or else they will wither and die.

It is important to keep these plants warm especially in places where the temperature of the environment drops below 55°F during winter. If you live in one of these places, it is best to grow Iron Cross Begonias indoors with the heater on.

Begonia masoniana Pests

Spider mites, mealybugs, and aphids are common pests for the Iron Cross Begonia. Infestations from these pests can be alleviated by using the right pesticides that specify that they are made to kill spider mites, mealybugs, and/or aphids.

For spider mites, good old soap and water can work well. If you want something stronger, you can buy chemical sprays that specify they are made to kill spider mites. Do note that spider mites are not insects and insecticides might not have any effect on them. Mealybugs can easily be dealt with by touching them with alcohol-dipped Q-tips.

Sprays are ineffective for them as they are protected by a white, waxy coating. For aphids, they can be easily controlled by having a ladybug live on your plant as they are known to take care of aphid problems. You can also use malathion, diazinon, and systemic insecticides.

It is important to check that your plants are free from these pests before moving them indoors to prevent them from propagating to your other plants.

The Iron Cross does not need pruning. However, dead leaves need to be immediately cut off as well as spent flower spikes after a bloom. Leaves may die due to lack of water or too low of a temperature. Adding a two-inch layer of mulch about an inch away from the plant’s roots is recommended to keep an even soil moisture and temperature. If you feel that your Begonia is getting too tall or leggy, you can pinch off stems to keep it at your desired size.

Begonia masoniana
Begonia masoniana

Watering the Iron Cross

Great care must be taken when watering your Iron Cross Begonia. These plants have rhizomatous roots that store water and will drown from overwatering. Their large leaves are also prone to mildew and fungus growth that can cause crown rot so it is best to keep the foliage dry, never misting it, and only watering the plant at its soil.

Only use room temperature water when watering the plant as using cold water could be detrimental. The amount of water that is needed depends on the stage of the plant’s growth. During its active growing stage, Iron Cross Begonias would need to be kept with evenly moist soil to sustain its growth.

Watering the soil about an inch a week will make sure that the soil stays moist while preventing it from getting soggy from too much water. The mulch shall also help in keeping the soil evenly moist. As growth slows, you can allow the soil to dry between waterings as it does not need as much water.

The Iron Cross Begonia also craves humidity more than water, being a native of the tropical regions of Southeast Asia. It is best to maintain an environment with at least 50% humidity.

If you have dry air indoors, you can use a humidifier to raise the humidity above 50%. If your plant starts to collapse or shrivel up, do not be tempted to increase the amount of water in the soil. Instead, cover the plant with plastic or use a glass cloche while keeping the plant at room temperature for 6 to 8 weeks.

This will help increase the humidity of the plant’s environment. It is also advisable to keep a keen eye on the plants when doing this as an increase in humidity might also promote fungal growth on its foliage.

Propagating Iron Cross

The Iron Cross Begonia can be propagated very easily by using stem cuttings. All you need to do is select a healthy leaf and cut it off its stem with a sterile knife at least 2 to 3 inches from the leaf.

Root the cut leaf in a moist, sterile potting mix and cover it with plastic or a glass cloche to increase humidity. If rooted indoors, keep the stem under fluorescent lighting. Roots will begin to grow in about two weeks and a plantlet will fully develop in eight weeks.

In Conclusion

The Iron Cross Begonia is a popular houseplant that can easily add some visual interest to your home or garden. They have an inimitable pattern marked on their bright, textured leaves, which makes them even more eye-catching and interesting. It does not require too much effort to grow and maintain, but the aesthetic value they add is difficult to match and will surely earn the praise of your guests.

As long as you give these plants the warmth, humidity, and nourishment that they need, they will definitely thrive and stay healthy for a long time. Of course, they will also greatly appreciate the additional love and care that you extend to them. Try growing them with other varieties of begonias and you are bound to have a beautiful arrangement as a result.


Hollie is a life-long gardener, having started helping her Dad work on their yard when she was just 5. Since then she has gone on to develop a passion for growing vegetables & fruit in her garden. She has an affinity with nature and loves to share her knowledge gained over a lifetime with readers online. Hollie has written for a number of publications and is now the resident garden blogger here at GardenBeast. Contact her at or follow on twitter

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