How to Plant and Grow Tuberous Begonia

Tuberous begonias are pretty plants with double blossoms reminiscent of camellia flowers or even mini roses. Though, as their name implies, they are perennials that grow from tubers, they are often grown as annuals. Tuberous begonias are hardy in the warm climates of Zones 9-11 but still prefer mild summery weather. They also grow well in containers and can make a colorful addition to your houseplant collection.

Tuberous begonias feature flowers available in almost every color (except blue and purple). They are monoecious, meaning they bloom with both female and male flowers on the same plant. The female blossoms appear first, often with single petals and a row of exposed flower parts. Then the showy male flowers appear with a cluster of petals concealing hidden flower parts.

Tuberous begonias bloom throughout the summer, providing a constant display of color. You won’t need to do much deadheading as the plants will naturally drop their spent blossoms. This can, of course, cause a messy situation—especially with hanging baskets in high-traffic areas. So, it's best to place container-grown plants where a sprinkling of petal debris won't be a problem.

Where to Plant Tuberous Begonia

Tuberous begonias are shade-loving plants, but benefit from exposure to morning or dappled afternoon sunlight. If the soil is right, they are just the thing to brighten up a garden bed under a tree. You could also use tuberous begonias to add color in north-facing spots where other plants might struggle from a lack of sun.

In most areas, tuberous begonias will need to be dug up and saved over the winter, so keep that in mind when placing your plants so you can easily access the tubers when it is time to overwinter.

Tuberous begonias also work well in containers on shady patios and porches with filtered sunlight. In fact, many gardeners prefer to grow tuberous begonias in containers so they can control the plant's soil, moisture, and nutrient levels—and move the plant if inclement weather is expected.

How and When to Plant Tuberous Begonia

You can start purchased or stored tuberous begonias in late winter or early spring (about 8 weeks before the last frost). Before planting, ready them for growth by placing them in a warm area (about 70 degrees Fahrenheit) with indirect sunlight. Within a few weeks, small buds should appear in the cupped area of the roots. After your tubers have sprouted, plant them in grow pots with a well-draining potting mix and water sparingly until each plant has one or two leaves.

After leaves have emerged, plant your tubers directly in the ground (about 8 to 12 inches apart) or in a container (about 5 inches apart) that has excellent drainage and cover them with about 1 inch of soil. Continue watering sparingly while the plants establish themselves.  

Tuberous Begonia Care Tips

Tuberous begonias may not classify as low-maintenance plants—especially when grown in the ground, but their pretty blooms are worth the extra effort.

If you are growing tuberous begonias in the ground, allow these plants to grow as long as possible up to the first frost. At this point, dig up the tubers with a small amount of soil around them and allow to dry in a sheltered location like a garage or shed. Once fully dried and after the stems have broken off, remove any remaining soil from the tuber and store in a cool, dry location until spring.

Light

Tuberous begonias generally do best in the morning sun and afternoon shade. Finding the right balance is key because exposure to some gentle sunlight will produce vibrant, colorful blooms, but too much sun causes leaves to scorch and can damage the tender petals of the plant.

Soil and Water

The primary key to success when growing tuberous begonias is choosing the proper soil. Keeping your plants protected from harsh weather is important too, but tuberous begonias require well-draining soil to thrive. Almost any type of soil will do, but if your soil is too wet, the tubers—which serve as storage systems for water and nutrients during dormancy—will rot. If your soil is heavy or clay-like, work in some decayed leaf mold and sand to loosen it up before planting.

If you are planting your tuberous begonias in a container, choose a good-quality, well-draining potting mix that contains humus or—even better—make your own using four parts decayed leaf mold, one part garden loam, and one part course sand.

When watering your tuberous begonias, be careful not to let the soil become too soggy. It is also important that the plants dry out a bit between watering, otherwise, the tubers are susceptible to rot. That said, tuberous begonias are not drought-tolerant and will need to be watered fairly frequently—most likely every two to four days or more during the hottest months. Check your plants often for signs of over or underwatering. If they look droopy or start dropping lots of flowers, the soil is likely too wet or too dry.

Temperature and Humidity

Tuberous begonias tend to be intolerant of very high temperatures (anything above 85 degrees) and high humidity. They are also sensitive to rain, wind, and other adverse weather conditions. Being native to high-altitude areas with cooler climates, they perform best with cool nights and shelter from the hot summer weather.

Tuberous begonias are also frost-tender and will likely suffer damage at temperatures below 50 degrees. If your region has cold winters, you may need to move the plants to a protected area or dig up the tubers and store them through the frosty months to be replanted again in the spring.

Fertilizer

Tuberous begonias are considered "heavy feeders," meaning they need regular fertilizer to sustain their constant blooming. Apply a diluted balanced liquid fertilizer every week to two weeks throughout the summer so the plant can put on the best display of blossoms. Stop fertilizing when the plant begins to decline in late summer or early fall.

Pruning

Tuberous begonias don’t require much pruning, but you can remove dead or diseased flowers and stems throughout the growing season to give your tuberous begonia ample airflow (or prevent faded blooms from littering the ground). With some varieties of tuberous begonia, pinching back or pruning early in the growing season will stimulate branching and could ensure more flowers in the summer months. If you plan to overwinter your plants, prune or cut them back in the late fall.

Overwintering

Like most plants with an underground storage system, tuberous begonias usually need a dormant period to encourage flowering and will typically enter dormancy in the fall and winter. During the dormant period, it is important to keep the soil dry because moisture will encourage rot and pests. As the soil warms up in spring, growth will typically emerge from the tuber.

In some climates, it may be necessary to overwinter your tuberous begonias by digging them up and storing them in a cool (around 50 degrees), dark place until the following spring. In the fall—when the plant begins to decline—stop feeding and reduce watering until the leaves start to turn yellow. If your tuberous begonias are planted in the ground, transplant them to pots before the last frost and bring them inside to die back. When the leaves fall off, cut the stems back to 3 or 4 inches (they will eventually drop as well). After the leaves fall, you can allow the soil to dry out until the tubers drop their stems.

Once the stems have dropped (resist the urge to help them) remove the dormant tubers from the pots, brush off the excess soil, and store them in individual paper bags in a dry, sheltered location (like a garage or shed). Check your tubers periodically throughout the winter for signs of rot or pest damage.

Potting and Repotting

When growing your tuberous begonias in containers, choose a container with excellent drainage that is large enough to accommodate the tuber with at least 1 inch of space all around. Don’t choose a container that is too large because container-grown tuberous begonias like to be slightly root bound.

Dormant or store-bought tuberous begonias can be started indoors in late winter or early spring (about 8 weeks before the last frost) by placing them in a warm area with indirect light to reacclimate and sprout. This should take a few weeks. After you have started your tubers, fill your chosen pot about halfway with soil, place the tuber bud side up, and cover it with a layer of potting mix. Water thoroughly once to stimulate growth and sparingly after that.

If you have an indoor-grown tuberous begonia that looks cramped or hasn’t been repotted in a few years), you can repot it in late winter or early spring before new growth emerges. Choose a container that is only slightly larger than the last pot, fill it with fresh potting mix, and gently remove your begonia from its old pot. Shake off the excess dirt and place the plant in the center, filling in around the tuber with fresh soil, but not tamping it down. Water your repotted begonia well and only slightly more frequently than usual in the following weeks as it re-establishes itself in the new pot.

Pests and Problems

Tuberous begonias are fussy about moisture levels, climate, and soil conditions and are famously prone to issues with rot. In particular, they are susceptible to stem rot, powdery mildew, and botrytis blight—especially if overwatered or planted in poorly drained soil. To keep these issues at bay, be mindful of overwatering, clean up dead or diseased foliage, and make sure there are at least 5 inches of space between plants in containers and 8 to 12 inches between plants in the ground.

Tuberous begonias are also prone to issues with mealybugs, whiteflies, and aphids, but are, for the most part, deer and rabbit resistant.

How to Propagate Tuberous begonia

Amateur propagation of tuberous begonia is typically done via division or seed. Tuber division can be done as your tuber is waking up from winter dormancy. If your tuber sprouts multiple buds cut one of the young buds from the tuber (no more than a couple of inches), coat it with plant fungicide, and insert it into a small grow pot or tray. Place the grow pot in an airtight bag and keep your new bud in a shaded area with filtered (not direct) light. Keep your grow pot in the bag on a warming pad to encourage growth (it may take several weeks). Once your new tuberous begonia takes root, start acclimating it in small stages to the environment in which it will grow. As it grows and acclimates, feed it with a diluted liquid fertilizer.

If you choose to propagate via leaf cutting, it will likely take several months, but you will develop a new tuber. Simply cut off a young, sturdy leaf and stem and insert it into a small pot filled with rooting medium. Keep the cutting in an airtight bag until it is rooted and then you can remove the bag. Gently feed your cutting with a diluted liquid fertilizer and continue growing as you would a normal potted tuberous begonia.

Types of Tuberous Begonia

'Go Go Yellow' Tuberous Begonia

Begonia 'Go Go Yellow' bears big yellow blooms against green foliage. It grows about 1 foot tall and produces a lot of flowers.

'Nonstop Bright Rose' Tuberous Begonia

Begonia 'Nonstop Bright Rose' bears glowing rose-pink flowers over a mounding plant with green foliage. It grows 10 inches tall and wide.

'Nonstop Deep Red' Tuberous Begonia

Begonia 'Nonstop Deep Red' bears rich red blooms against rich green foliage. It grows 10 inches tall and wide.

'Nonstop Mocca White' Tuberous Begonia

Begonia 'Nonstop Mocca White' bears pure-white flowers on chocolate-brown foliage. It grows 12 inches tall and wide.

'Nonstop Fire' Tuberous Begonia

Begonia 'Nonstop Fire' is a new variety with blooms in vibrant shades of yellow, gold, orange, and red. The 4-inch-wide flowers contrast nicely against the deep green foliage. It grows 10 inches tall and wide.

'Nonstop Deep Rose' Tuberous Begonia

Begonia 'Nonstop Deep Rose' bears rich rose-pink flowers over a mounding plant with green foliage. It grows 10 inches tall and wide.

'Nonstop Yellow' Tuberous Begonia

Begonia 'Nonstop Yellow' bears lovely bright yellow blossoms over rich green foliage. It grows 10 inches tall and wide.

'Solenia Cherry' Tuberous Begonia

Begonia 'Solenia Cherry' has 3-inch-wide fully double red blooms. It grows 10–12 inches tall and wide, and its compact mounded habit suits it well for growing in containers.

'Nonstop Mocca Deep Orange' Tuberous Begonia

Begonia 'Nonstop Mocca Deep Orange' combines intensely orange 4-inch-wide blooms with chocolate-brown leaves on compact mounded plants. It grows 12 inches tall and wide.

'Nonstop Rose Petticoat' Tuberous Begonia

Begonia 'Nonstop Rose Petticoat' shows off two-tone pink flowers over rich green foliage. It grows 10 inches tall and wide.

Companion Plants for Tuberous Begonia

Tuberous begonias are tropical plants, so they pair well with other plants that enjoy similar growing conditions like caladiums, impatiens, elephant ears, and ferns.

Impatiens

Impatiens are hardy in Zones 10 and 11 but often grown as an annual in other areas. They love shaded or semi-shaded locations and prefer humus-rich, moist, well-draining soil with a slightly acidic pH of 6 to 6.5. Impatiens and tuberous begonias are often paired in container gardens for blooms that last all summer long—even in the shade.

Lobelia

Lobelia erinus offers mounds of intense purple, blue, white, or pink flowers in the fall or spring in most regions where it is hardy (Zones 2-11). It grows well in partial shade like the tuberous begonia. This type of lobelia can handle slightly more sun exposure than the begonias—so it won’t mind getting about 4 to 6 hours of full sun—but too much hot sun may cause the plant to stop blooming temporarily. It also grows well in containers and makes a lovely spiller for hanging baskets or planters.

Coleus

Coleus is a rockstar in a shade garden, offering colorful foliage in intense shades of chartreuse and burgundy. There are even trailing varieties that will spill over the edges of garden boxes and planters, bringing color to shady corners of patios and landscapes. Coleus can be grown in Zones 2-11.

Caladium

Caladium, like tuberous begonia, is hardy in warmer tropical regions (Zones 9-11). It features colorful, arrowhead-shape leaves with amazing color patterns in white, pink, red, and green. Caladium grows best in partial shade or filtered sun (bright sun may scorch the leaves) and thrives in containers alongside begonia, impatiens, and fuchsia.