Begonia Plant: How To Grow and Plant Care

Whether you’re an indoor plant enthusiast, or you have the room and the means to grow them outdoors, there’s a begonia for every taste, planting scheme and space available.

Begonias are diverse plants which have definitely endured for as long as we’ve been growing them. They have fallen out of favor and returned with a resurgence in popularity repeatedly, and thanks to their countless numbers of cultivars, these are beautiful plants which work well in any garden.

Interested in growing your own? Here’s what you need to know.

At a Glance: What You Should Know About Begonias

Begonias come from subtropical and tropical parts of the world, which are also humid. The Begonia genus is huge, consisting of more than 2000 different species. 

Some are grown as houseplants for their gorgeous leaves and flowers, while others are cultivated as tender perennials for their huge ornamental value in the garden. 

Most of those which are sold as houseplants steal the show with their foliage, coming in many different colors and patterns.

The ones that are grown outside are valued for their incredibly vivid flowers, which come in various shapes and sizes, and it’s interesting to note that these particular begonias have colored sepals, but no actual petals. Some are perfumed, too.

There are many different types of begonia. Some grow from rhizomes, some from roots, and some from tubers. 

You can get bedding type begonias, which are small and upright, trailing begonias, and climbing begonias, so there’s one for every space imaginable, whether that’s indoors or outdoors.

A Note on Toxicity

It’s worth mentioning that begonias contain toxic sap, which is harmful to both humans and animals. In which case, if you have particularly curious pets or children, begonias may not be for you, or you need to keep them well out of reach.

While all parts of the plant are harmful if ingested, the greatest danger is in the stems and tubers, which is where most of the toxins are concentrated. 

Signs of poisoning include drooling, swelling of the tongue and lips, and a burning sensation in the mouth. 

If you suspect that your pet has eaten part of your begonia, get them checked out by a vet as soon as possible, taking either a sample of the plant tissue or the name of the cultivar with you.

Should You Grow Begonias Outdoors or Indoors?

Begonias can be grown outdoors or indoors, depending on the type you go for. Even in colder climates, begonias will thrive at least for the summer months, but those with ornamental foliage are best kept indoors, as they aren’t as hardy as the other types.

Different Types of Begonias to Grow

The sheer amount of choice when it comes to picking begonias can be overwhelming, but it helps that they can be divided into three broad categories, and these typically have different uses.

Fibrous-Rooted Begonias

As the name might suggest, fibrous begonias grow from a normal root system, and feature more petite, daintier flowers and leaves. 

They are treated as annual plants by gardeners across the world, used to fill in gaps in borders or to provide a wealth of color in containers. This type of begonia includes the wax begonias, Begonia semperflorens.

Foliage Begonias

Commonly grown as houseplants, or brought outside during the height of summer, foliage begonias are grown for their stunning leaves, which come in a huge array of colors, shapes, and patterns. 

You are probably familiar with the Rex Begonia, which is an award-winning type with a huge number of different cultivars and colors.

The foliage begonia group also includes the cane type begonia, which boasts huge foliage in different colors and patterns, such as Begonia maculata

Most cane begonias need support, as their leaves are too heavy and will drape down from the plant, but give them a trellis or a moss pole, and they will happily climb.

Tuberous Begonias

Tuberous begonias grow from, as you might guess, tubers. These plants have a lot of ornamental value in gardens, where they are grown for their huge, dramatic flowers from summer into autumn.

They can’t tolerate freezing temperatures, so they are usually treated as annual plants, but you could try overwintering them, too.

How to Use Begonias in Your Own Garden

Tuberous begonias are best used in large containers and hanging baskets, where the vivid tones of red, white, orange, pink, or yellow can really show off. 

As many types of tuberous begonia feature very heavy flowers, they make the perfect plant for hanging baskets, where they will provide long-lasting color throughout summer, and well into autumn, if the weather is kind.

Fibrous begonias are best for pots and gaps in your borders, which could really do with an injection of color for the summer.

Save most foliage begonia types indoors, where they are bound to create their own focal point all year round. 

How to Make Sure Your Begonias Thrive

Sunlight and Soil Needs

Most begonias thrive best in partial shade, as direct sunlight is much too strong for them. 

However, you can get some which can withstand direct sunlight, such as the wax begonias, perfect for bringing pops of color into your borders.

You can sit them in a bright position if there’s little chance of them getting any direct sun, especially if you’re growing your begonias indoors, where they will need all of the light they can get.

In terms of soil, begonias love fertile soil which drains well. As you might imagine, these beautiful plants are vulnerable to rot if the soil gets saturated too much without drying out, or if the temperature of the soil plummets. 

Temperature and Humidity Requirements

Exactly what kind of temperature your begonia requires depends on the type of begonia you go for. The Rex Begonia, for example, needs a much warmer temperature than fibrous begonias, and it’s also more demanding when it comes to humidity, meaning that it should stay inside year-round if your garden cannot fulfill these requirements.

Outside, most begonias will be fine with normal levels of humidity, as long as there’s a few of them close together, which helps create a small microclimate. Temperatures below 50˜F (10°C) will make these plants suffer, and an ideal temperature for most begonias is 71°F (21°C).

Tuberous begonias have heavy flowers and weak stems, so they need a sheltered spot. Most types will drop their flowers if the temperatures get too hot.

When to Water a Begonia

All begonias require moist soil in order to thrive, but this is where it gets a little tricky. You don’t want to saturate the soil too often, as the plants can develop root rot quickly. 

Always check the soil before you water. The best time to water begonias is when the top inch of compost has nearly dried out.

Should You Feed Begonias?

Begonias benefit from a balanced, organic fertilizer in the summer months when bloom production is at its highest. 

Feed them every two weeks during the summer, with a weak dose of fertilizer when they require watering.

How to Propagate Begonias

Depending on the type of begonia you go for, this will dictate what method of propagation you need to use. 

Tuberous begonias, for instance, propagate well through cuttings. In spring, take new shoots off the tubers with your hands, and pot them up in small pots, putting them in a heated prop box somewhere shady.

It’s worth knowing that if you collect seeds from tuberous begonias, it’s very rare that they’ll turn out like the parent plants, so always take cuttings where you can.

Foliage begonias are very easy to propagate, and you can do this through taking cuttings from the leaves. Place the leaves in moist sphagnum moss, into a heated propagator.

Fibrous rooted begonias are easy to raise from seed, and this is best done during the first few weeks of spring.

Begonias: Common Problems to Watch Out For

Root Rot

Root rot is one of the biggest problems when it comes to growing begonias, as they can be rather picky about how much water they get. 

Keep the soil well-draining, by adding some grit if you need to, and let the top two inches of the soil nearly dry out in between watering to stop root rot from killing your begonias.

Vine Weevil

In begonias which are grown in pots, vine weevil can be a difficult pest to control. The larvae hatch into the soil, eating the roots of the plants. You may also notice tiny notices in the edges of leaves.

Ways of preventing the risk of vine weevil include inspecting any newly-bought plants at the roots for larvae, squashing adult bugs, and encouraging birds and other predators into your garden.

Powdery Mildew

Powdery mildew is the second-biggest fungal concern you’ll have to deal with when it comes to begonias. It often appears from mid-spring onward, and attacks those which produce yellow flowers the most.

Make sure you give your plants plenty of airflow, allowing the air to circulate around the leaves. Take off any dead or diseased leaves as you notice them, and this will help stop the spread.

Final Thoughts

Begonias are some of the most beautiful plants you can grow indoors and in your garden. They come in nearly every color you can imagine, both in terms of the foliage and the flowers, and attract a wealth of pollinators into your garden.

It also helps that they are easy to look after once you master their watering requirements, ensuring they’ll be a staple of your garden or houseplant scheme for years to come.

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