How to Grow and Care for Begonias

Begonias are perfect for a long-blooming splash of color on shady porches. In cooler climates, you can grow these tropical beauties as houseplants or annual flowers in containers, hanging baskets, or beds. Begonias thrive in part shade and appreciate evenly moist, fertile soils. Their roots are toxic to some animals.

Learn about the many different types of begonias and how to grow them with our comprehensive care guide.

How to Care for Begonias

Begonia care varies depending on their class and cultivar, but the main requirements include:

• Position in indirect sunlight or shade
• Water to ensure evenly moist not soggy soil
• Plant in well-draining soil that's rich in organic matter
• Fertilization requirements vary depending on the species

Light

Begonias are forest understory plants in their native habitats, so they usually do best in partial sun positions outdoors. Some types, like wax begonias, will flower consistently in full sun. Indoors, begonias appreciate a position in bright but indirect light. Too much sun can wilt the delicate petals or cause the foliage colors to fade.

Soil

Begonias thrive in porous, slightly acidic, humusy soil. Excellent drainage is a must. Peat-based soils with plenty of organic matter, including leaf mold, are good. Potting mixes for African violets are a convenient option.

Water

Water your begonia thoroughly once the top inch of the soil is dry. While these plants appreciate even moisture to produce the best blooms, avoid overwatering begonias. Soggy soils can lead to root rot. Always water at the base of the plant, as these plants can also be susceptible to foliage fungal diseases, such as powdery mildew.

Temperature and Humidity

Begonias grown indoors do best with consistent temperatures ranging from 65 to 70 degrees Fahrenheit. Most varieties won't tolerate temperatures below 55 degrees Fahrenheit. Tuberous begonias planted in the garden should cope with cool late summer evenings but go dormant once the nights and days turn colder.

Being tropical plants, begonias like some humidity (typically, just under 50%). In houses with dry air, placing a saucer of water near your begonia or using a humidifier in the room can help the plant stay healthy. Keep garden begonias sheltered, as high winds can damage their fragile flowers and foliage.

Fertilizer

For rhizomatous begonias grown indoors, a basic water-soluble fertilizer mixed to quarter or half strength and applied to moistened soil in spring will help promote blooms. Tuberous begonias are somewhat more hearty feeders and like a 5-1-1 fertilizer (such as organic fish emulsion) applied twice a month during the blooming season. For hardy begonias, mix a bit of diluted fertilizer with some compost or peat moss and apply sparingly (too much fertilizer may harm the leaves).

Indoor vs. Outdoor Care Differences

While shadier conditions are preferred outdoors, bright filtered light is best for indoor begonias. You also need to account for drier conditions indoors, so keeping your begonias away from drying HVAC vents and adding a humidifier or a water-filled pebble tray under their pots is usually beneficial.

Types of Begonias

There are many begonia varieties to choose from, with over 2,000 species in the genus and thousands more hybrids and cultivars. Below is a breakdown of the four basic types of begonias to help you choose one best suited for your conditions and location.

Cane Begonias

These tall plants, sometimes called angel wing begonias, feature showy, wing-shaped foliage on erect stems that can reach over 6 feet tall.

The cascading clusters of flowers are usually white, red, or pink. They tend to be easier to grow than many tuberous and rhizomatous begonia types and are more forgiving of temperatures and humidity levels.

The polka dot begonia (Begonia maculata) is one of the most well-known and striking species. It features narrow, deep green leaves with silver spots and pale pink flowers.

Wax Begonias

Semperfloren begonias (also known as wax begonias) are fibrous-rooted plants with striking waxy, bushy, heart-shaped foliage and clusters of long-blooming summer flowers. They grow easily from seed and are popular houseplants and annual bedding plants.

One of the biggest advantages of compact wax begonias is that they can often grow in full sun as well as partial shade. They also handle heat and drought conditions better than some other begonia varieties.

Consider the 'Prelude Series' of cultivars in hot, wet regions or the 'Cocktail Series' of cultivars for their striking bronze foliage.

Rhizomatous Begonias

Rhizomatous begonias, including the popular Rex begonia varieties, grow from creeping rhizomes (thick underground stems). Their bold patterned foliage has a compact, mounding habit, and they typically flower in late winter and spring.

This large group of adaptable, cool-temperature begonias can grow outdoors all year if winters are particularly mild. If they have striking foliage patternation, they often require higher humidity.

Tuberous Begonias

As the name suggests, these begonias grow from tubers you can dig up in fall and overwinter indoors to replant the following year.

Unlike many other begonia varieties, they are prized for their large flowers rather than their foliage. They often have a trailing habit, making them ideal flowers for hanging baskets.

The hardy begonia (Begonia grandis) is a tuberous begonia that can survive winters in USDA zones 6 to 9, making it more winter hardy than most begonia species.

Pruning

In addition to deadheading flowers, older begonias may occasionally need light pruning to remove dead or damaged stems or leaves and tidy the shape of the plants.

Pruning is best done in early spring in mild regions, as removing old stems helps promote healthy new growth. Don't wait too long, though, as you don't want to cut off budding stems and risk reducing bloom potential.

When pruning begonias for shape, don't cut off too much of the stem. Otherwise, the plant will need a lot of energy to recover. Instead, take off only the top portion of the stem directly above a growing node or bud.

How to Propagate Begonias

Begonias may be propagated from stem or leaf cutting cuttings or rhizome or tuber division. Here's how to propagate begonias from stem cuttings:

1. Place a 2 to 3-inch stem cutting with the bottom leaves removed in water in indirect sunlight. The water should cover the nodes where the leaves were removed.
2. Refresh the water at least once a week.
3. Once roots form, transplant into the ground or potting soil.

You can also press rhizome or tuber cuttings gently into moist potting soil. They should begin sprouting new growth in a few weeks.

Potting and Repotting

Begonias grow well in containers with good drainage, indoors and outdoors. To keep them thriving, they need regular repotting to give the creeping tubers or rhizomes room to grow. You'll know it's time to repot if you lift the plant from the pot and the potting soil holds together around the roots. Gently lift out the roots or tubers and place them in a new pot with fresh potting soil, then water lightly.

Don't go too large with your new pot. One around 2 inches bigger in diameter should be enough. If the pot holds too much potting soil, your begonia will struggle to take up water quickly enough. Leaving the soil soggy for too long encourages root rot.

Common Pests and Plant Diseases

Generally speaking, begonias are not bothered by many pests or diseases. Root rot can occur due to overwatering, as can stem rot or powdery mildew.

The main pests that affect begonias include mealy bugs, spider mites, snails and slugs (the latter two enjoy munching the leaves and are easy to remove by hand). However, be careful when removing pests, as begonia foliage can be sensitive to insecticidal soaps. It's always best to test on an individual leaf first.

Overwintering

How you handle your begonias overwinter depends on the type you have and your local conditions. If you have a variety that doesn't go dormant and you live in a region with mild winters, you can continue to enjoy your begonias outdoors all year round. If temperatures drop below 60 degrees Fahrenheit, bringing your begonias indoors is best unless you want to treat them as annuals.

For winter flowering rhizomatous begonias and cane types, keep them in bright but indirect light and lightly water and fertilize during this time. Rex begonias are more challenging to overwinter indoors, as they need high humidity levels to thrive and prefer more regular watering and fertilization.

Tuberous begonias go dormant in the winter, so you should start reducing watering frequency through the fall, allowing the tops of the plants to die back. When you are ready to remove the tubers, you want the soil to be completely dry.

Cut away the stems and store them under a layer of sawdust or vermiculite in a dry spot in your home where temperatures are between 40 and 50 degrees Fahrenheit. After a few weeks of curing, remove the soil that remains around the tuber before returning it to the storage spot.

You can replant the tubers in the spring. Starting them off planted near the surface of some damp potting soil on a bright windowsill indoors allows you to transplant them once you see new stems poking out the soil and the danger of frost has passed.

How to Get Begonias to Bloom

Bloom Months

In summer, begonias can bloom for weeks at a time, from summer through late autumn. When kept indoors, they're capable of blooming nonstop, depending on the variety. Tuberous begonias do go through a period of dormancy when flowers and foliage die back for a few weeks, but other types of begonia can bloom constantly all year long. Be sure you're following care instructions for the specific type of begonia you have.

What Do Begonia Flowers Look Like?

Begonia flowers bloom in single or double flowers that are red, pink, yellow, white, or orange.

How to Encourage More Bloom

Using fertilizer regularly can help keep begonias blooming. The trick is to apply with a light touch, using diluted liquid fertilizer. Never apply fertilizer when the soil is dry. Regular deadheading is also essential to promote maximum blooms.

Common Problems With Begonias

When there’s a problem with your begonias, often there are early warning signs to look out for.

Flowers Wilting

If the flowers or leaves seem to be wilting or turning brown, your begonia may be getting a bit too much bright sunlight. Move to indirect light or partial shade.

Plant Not Blooming

If your begonia plant is not flowering, it could be due to too much or little water, extreme temperatures, or not enough light. Ensure optimum growing conditions to encourage bloom.

From: thespruce