How To Grow And Care For Begonias

Keep these beauties cool, and they will show off all summer long.

Khara Scheppmann has 12 years of marketing and advertising experience, including proofreading and fact-checking. She previously worked at one of the largest advertising agencies in the southwest.

If you are looking for a plant that produces flowers in beautiful colors and does well in the shade or containers, a begonia is just what you need. With more than 2,000 species to choose from, begonias can grow 8 inches to over 5 feet tall and are available as annuals, perennials, shrubs, and climbers.

Flowers come in various colors, including red, white, pink, and yellow. They can be single or double blooms with delicate, ruffled, or smooth petals. Some begonias have less showy flowers and are grown primarily for striking foliage that is polka-dotted or frosted with silver or plum. Begonias grow well in flower beds, container gardens, or window boxes.

Relatively easy to grow, begonias prefer warm climates and rich, fertile, well-drained soil. Plant them after the last spring frost when the soil is warm. Seeds take a few weeks to months to germinate, and some begonia varieties grow quickly. Most importantly, begonias cannot tolerate freezing temperatures—bring them indoors before the first frost, but be aware that these plants are toxic to animals. Also, begonias can be invasive in milder environments due to their spreading nature.

Begonia seeds are one of the smallest in the world of flowers. One ounce of seed can produce as many as 1 million seedlings, which can cause issues in particular environments as begonias can be invasive due to their spreading nature in roadsides, harvested forests, old fields, overgrazed pastures, and waste places. A flower symbolizing "beware," the begonia is related to pumpkins, squash, gourds, cucumbers, and melons.

Caring for begonias is relatively easy in good soil conditions. You can also grow begonias indoors, but meeting their light and humidity needs might be more challenging.

Begonias thrive in warm environments but, depending on the variety, might need full or partial sunlight. Most begonias do best when planted in an area with morning sun and afternoon shade. Allow enough sunlight to keep the soil moist and healthy. Don't plant in direct sunlight in regions that experience scorching summers.

Begonias are relatively tolerant of any well-draining soil. Keep the soil damp, but do not oversaturate it because it can cause rot. If the flower bed or garden area does not contain soil rich in organic matter, supplement it with fertilizer. When growing begonias in containers or hanging baskets, use a soil mixture of leaf mold, garden loam, and coarse sand to help with soil moisture retention and draining. Potting mix can substitute for leaf mold if unavailable.

Keep the soil continuously damp but do not saturate the soil. If the first few inches of soil are dry, you can tell if your begonias need more water. Allow the soil to drain entirely before watering again because the wet or soggy ground can cause root rot. Also, water the plant base instead of the leaves because wet foliage causes fungal growth.

Due to their native environment, begonias thrive in warm, humid areas. Depending on whether you intend to keep begonias as annuals or perennials, these flowers grow outdoors in areas where temperatures stay above 60 degrees Fahrenheit or indoors in climate-controlled rooms. One exception is the hardy begonia (B. grandis), which can survive winter temperatures down to 23 degrees.

Adding a humidifier indoors can help simulate the humid climate begonias want, making it easier to grow as a perennial.

Begonias are heavy feeders, but should only be fertilized during the growing season when temperatures remain above 60 degrees. For best flower production, use a phosphorus-heavy flower fertilizer like 15-30-15. With water-soluble fertilizers, dilute to half strength and use twice a month while begonias are actively growing. Never fertilize young seedlings or cuttings, and stop fertilizing when the plant's growth slows down in October.

sasimoto / Getty Images

Elizabeth Fernandez/Getty Images

Begonias need pruning to maintain healthy stems, which can get leggy if left untouched. Cut branches depending on your begonias' growth, which will encourage new growth as stems emerge from the pinched point. Since begonia stems break easily, pruners or garden shears are not necessary.

Begonias can grow as annuals or perennials, but when bringing annuals indoors, these plants often suffer shock or grow leggy, so propagating new plants is an easy, effective solution. Begonias propagate differently depending on the varieties, but often using cuttings is the simplest way to achieve the best results. Here's how to propagate begonias using stem or leaf cuttings:

If propagating with a large leaf, cut the mature leaf with a sharp knife where it meets the stem. Cut the end of the leaf into a point and follow the directions for stem cuttings.

There are several ways to start growing begonias. Sowing seeds in a starter tray, potted plants, or tubers are all options after the last frost. Growing begonias from seeds or fibrous roots can start indoors, but gauge when the last frost is expected in your area, so you are prepared to transplant them outdoors—start seeds usually three months prior.

Begonias do well in pots and add a pop of color to container gardens. They are not long-lived but can live two or three years. Wait until the threat of frost has passed. Choose a pot with drainage holes and fill it with potting soil mixed with compost. Place the container where it will get full sun or shade, depending on what the specific variety needs. Begonias like to be slightly rootbound, so look for small pots and gradually move up one size when they need repotting. Add fertilizer monthly and let the top 2 inches of soil dry out between waterings. Bring potted begonias indoors during winter in colder climates where the temperature gets below 45 degrees.

Winter care depends on the variety of begonias, tuberous or fibrous. Move begonias grown from rhizomes indoors during the winter and regularly deadhead the plant to maintain its appearance and health, which will also prevent diseases. Tuberous begonias need little watering to maintain growth. Frequent watering will encourage new growth or rot the bulbs. Continue pruning weak sprouts if the growth continues, and suspend watering until the spring. Remove moldy or rotten tubers.

Fibrous or root-bound begonias act like other houseplants over the winter, meaning they need indirect sunlight, healthy and moist soil, and infrequent watering. Do not scorch the plants with too much direct light or heat. Wait until you are sure the final frost of the season has passed before moving plants outside—slowly introduce begonias to the spring temperatures so they can adjust.

If you have a tuberous begonia, these plants will die back yearly, so digging and storing the tuber to replant the following year will help protect the roots. You can also bring pots indoors once the plants become dormant, leaving them in a spot that is cool, dry, and dark until spring.

Begonias are susceptible to diseases including stem rot, Botrytis blight, and powdery mildew when growing in humid conditions without proper air circulation or in oversaturated soil.

Pests can be an issue for begonias, as these plants are sensitive to insecticidal soaps, so prevention is critical. Mealybugs, spider mites, scales, and thrips are often associated with begonias. Insecticidal soaps will treat these pests. Use it sparingly at first to test for leaf scorch.

Begonias can bloom for up to six months in partial sun and ideal temperature conditions. Adding fertilizer every two weeks in pots and containers can help promote new growth—garden beds only need fertilizer every three to four weeks. Fertilizer or soil high in nutrients will help promote begonias to bloom, but use a slow-release formula to not pull energy from the flowers by creating more foliage and roots. Begonia stems are pliable, so use your fingers to remove spent blooms, deadheading the wilted or dead flowers to make room for a new showing.

Begonias are susceptible to diseases and garden pests. Some are more challenging to treat, but knowing what can go wrong will help you understand what to look for in your plants.

Browning leaves result from too much direct or harsh sunlight. Although begonias prefer well-drained soil, underwatering is still an issue that can cause foliage to dry out and brown. Additionally, if growing begonias indoors or in unideal climates, take precautions to ensure enough humidity near the plants. Do not place indoor begonia plants near air vents.

Yellow leaves are a classic sign of overwatering—gauge when begonias need more water by feeling the soil with your hands. Use a well-draining container and amend the potting soil with peat. If yellowing persists, white spots might appear, signifying powdery mildew is present. Use a fungicide to treat the affected foliage, but do not scorch the leaves when spraying—begonias are susceptible to leaf scorch.

Several pests enjoy begonias, including slugs and snails. One of these pests might have infected the foliage if it appears to have holes throughout or a slimy residue. You can remove slugs and snails by hand. Diatomaceous earth is a powder made from sediment of fossilized algae and found at garden centers, which can also help slow down pests. Reapply the solution after heavy rain.

Some begonias do come back each year. Perennials like hardy begonias (Begonia grandis) will come back with proper growing conditions in Zones 6-9. Save the tubers of tuberous begonias and replant them the following spring.

Begonias grow well with shade-loving plants like ferns, bleeding hearts, and hostas in the garden. Impatiens, pansies, and coleus are good container companions. Pair trailing begonia with petunias or verbena for colorful hanging baskets.

Begonias bloom continuously from their first flowering until the first frost. Give them adequate water, some shade, and regular fertilizer to keep them blooming. Deadhead the blooms to encourage more.

American Society for the Prevention of Cruelty to Animals. Begonia.

University of Florida Center for Aquatic and Invasive Plants. Begonia cucullata.

Begonia grandis. North Carolina Extension Gardener Plant Toolbox.