Table of Contents
- Introduction
- Selecting the Best Begonias for Your Garden
- Choosing the Right Spot: Light and Soil
- Timing Your Planting
- How to Plant Begonia Tubers
- Ongoing Care and Maintenance
- Growing Begonias in Containers and Baskets
- Overwintering and Storage
- Troubleshooting Common Issues
- Simple Propagation
- Conclusion
- FAQ
Introduction
Finding the perfect flower for a shady corner is one of the most rewarding moments for any gardener. While many plants struggle without direct sun, begonias thrive in filtered light, bringing brilliant color to the quietest parts of your yard. These tropical beauties are famous for their lush foliage and rose-like blooms. They turn dim porches and under-tree gardens into vibrant displays that last from early summer until the first frost.
At Longfield Gardens, we enjoy helping you bring these spectacular plants to life. Begonias are surprisingly easy to grow once you understand a few simple preferences they have for soil and water. This guide is for anyone who wants to enjoy bigger, brighter blooms in containers, hanging baskets, or garden beds. We will walk you through the entire process, from choosing the right tubers to storing them safely for next year.
Whether you are a busy beginner or a seasoned pro, growing begonias is an achievable way to add professional-looking flair to your landscape. With just a little bit of planning, you can enjoy a season full of incredible texture and color.
Selecting the Best Begonias for Your Garden
Before you get your hands in the dirt, it helps to know which type of begonia fits your vision. Most home gardeners focus on tuberous begonias because they produce the largest and most decorative flowers. These plants grow from a thickened root called a tuber, which stores energy and allows the plant to return year after year with proper care.
Upright Tuberous Begonias
Upright varieties are the workhorses of the shade garden. They typically grow 12 to 18 inches tall and feature sturdy stems that hold large, heavy flowers. These are excellent for garden borders or as the "thriller" in a mixed container. Within this group, you will find different flower shapes:
- Double Begonias: These feature many layers of petals and look very much like traditional roses or camellias.
- Fimbriata Begonias: These have unique, fringed edges on their petals, giving them a ruffled, carnation-like appearance.
- Picotee Begonias: These are prized for their color patterns. The petals are one color with a contrasting edge in a different shade.
- Bouton de Rose: These varieties produce flowers that resemble a tightly furled rosebud in the center.
Cascading or Pendula Begonias
If you want flowers that spill over the edges of a pot, cascading begonias are the perfect choice. Also known as trailing or pendula begonias, these varieties produce many smaller blooms on arching stems. They are the gold standard for hanging baskets and window boxes. Because the stems are flexible, they catch the breeze beautifully and provide color from every angle.
Wax and Fiberous Begonias
While we focus largely on the large-flowered tuberous types, you may also see wax begonias. These are smaller, fibrous-rooted plants often used as bedding annuals. They have waxy leaves and smaller clusters of flowers. They are very tough and can handle more sun than tuberous types, but they do not produce the massive, show-stopping blooms that tubers provide.
Key Takeaway: Choose upright varieties for garden beds and large pots, and select cascading pendula varieties for hanging baskets to get the best visual impact.
Choosing the Right Spot: Light and Soil
Success with begonias starts with the "right plant, right place" rule. Because they are native to forest floors in tropical regions, they have specific needs for light and drainage.
The Perfect Light Balance
Begonias are famous for being shade lovers, but "shade" can mean many things. For the best results, aim for filtered or dappled sunlight. A spot under a tall tree or a porch that faces east is usually ideal.
In most regions, begonias appreciate 2 to 4 hours of morning sun followed by shade during the heat of the afternoon. If they get too much direct midday sun, their leaves may scorch or turn brown at the edges. Conversely, if the shade is too deep, the plant will grow leggy and produce fewer flowers. If you notice your plant stretching toward the light, it is a sign it needs a slightly brighter location.
Understanding Drainage
Drainage is simply a measure of how fast water leaves the soil. Begonias have fleshy stems and roots that hold a lot of moisture. If the soil stays saturated, the tubers can rot.
To test your soil, observe it after a heavy rain. If puddles remain for more than five or six hours, the soil is likely too heavy in clay. You can improve drainage by adding organic matter like compost or coco coir. For containers, always use a high-quality, soilless potting mix. These mixes are designed to be airy and light, which keeps the roots healthy.
What to do next:
- Identify a shady spot that gets morning sun.
- Check for drainage holes in any containers you plan to use.
- Purchase a fresh bag of high-quality potting soil.
Timing Your Planting
Begonias are tropical plants, which means they love warmth and have no tolerance for frost. Timing is the most important factor in getting your begonias off to a strong start.
Starting Indoors for Earlier Blooms
Because begonias can take 12 to 15 weeks to go from a dry tuber to a full-blooming plant, many gardeners choose to start them indoors. We recommend starting your tubers about 8 to 12 weeks before the last expected frost in your area. This gives the plants a "head start" so they are already leafy and vigorous by the time the weather warms up.
Waiting for the Right Temperature
If you prefer to plant directly outdoors, patience is a virtue. Do not move your begonias outside until the soil is warm and the nighttime temperatures stay consistently above 60°F. Even a light frost will damage the tender foliage. If a surprise cold snap occurs after you have planted, simply cover your garden plants with a frost blanket or bring your containers into a garage or shed for the night.
How to Plant Begonia Tubers
Planting a begonia tuber is a simple process, but there is one specific detail you must get right: which side faces up.
Identifying the Top
If you look closely at a begonia tuber, you will notice one side is slightly indented or concave, like a shallow bowl. This is the top. The smooth, rounded side is the bottom. The stems and leaves will grow out of the indented side, while the roots grow from the bottom and sides. If you can’t tell which side is which, you can plant the tuber on its side; the plant will naturally figure out which way to grow.
Planting Depth and Spacing
Begonias do not like to be buried deeply. In fact, planting them too deep is a common reason they fail to sprout.
- Placement: Place the tuber in the soil with the indented side facing up.
- Depth: Cover the tuber with only about a half-inch to one inch of soil.
- Spacing: In garden beds, space tubers 10 to 12 inches apart to allow for airflow. In a 12-inch pot, you can plant two or three tubers for a very full look.
The First Watering
After planting, water the soil just enough to settle it around the tuber. Be very careful not to overwater at this stage. Until the tuber develops roots and starts sending up leaves, it cannot process much water. Keeping the soil slightly damp—but never soggy—is the secret to a healthy start.
"The indented side of the tuber should always face upward. This is where the new growth will emerge, so keep it close to the soil surface for the easiest start."
Ongoing Care and Maintenance
Once your begonias are established and growing, they are relatively low-maintenance. Following a simple routine will keep them blooming beautifully until autumn.
Watering Correctly
Begonias prefer "consistent moisture." This means the soil should feel like a wrung-out sponge. We recommend the finger test: stick your finger an inch into the soil. If it feels dry, it is time to water.
When watering, try to apply the water directly to the soil rather than splashing the leaves. Wet foliage in a shady environment can sometimes lead to mildew. If you are growing in containers, remember that they dry out much faster than garden beds, especially in the heat of mid-summer. You may need to water container-grown begonias every day or two during a heatwave.
Feeding Your Plants
Begonias are "heavy feeders," meaning they use a lot of energy to produce those massive flowers. Once the plant has several sets of leaves, start a regular fertilizing schedule. A balanced, water-soluble fertilizer applied every two weeks works well. Alternatively, you can use a slow-release fertilizer at planting time. If you want to encourage more blooms, look for a fertilizer with a slightly higher middle number (phosphorus), often labeled as a "bloom booster."
Deadheading and Grooming
To keep your plants looking their best, remove flowers as they begin to fade. This process, called deadheading, prevents the plant from wasting energy on seed production and encourages it to keep making new buds. Simply pinch or snip the flower stem off where it meets the main stalk. You should also remove any yellowed or damaged leaves to maintain good airflow around the plant.
Support for Tall Varieties
Some upright double begonias produce flowers so large that the stems might lean under the weight. You can use small bamboo stakes or specialized plant supports to keep the stems upright. This protects them from snapping during a heavy rain or wind.
Growing Begonias in Containers and Baskets
Containers are perhaps the best way to showcase begonias. They allow you to control the soil quality perfectly and move the plants around to find the best light.
Choosing the Right Pot
Begonias have relatively shallow root systems, so they don't need incredibly deep pots. However, they do need space to spread out. A pot that is 8 to 12 inches in diameter is a great size for a single tuber. Ensure there are plenty of drainage holes. If you have a decorative pot without holes, use it as a "cachepot"—keep the begonia in a plain plastic nursery pot with holes and set that inside the decorative one.
The Benefit of Large Containers
In our experience, larger containers are actually easier to manage than small ones. A larger volume of soil holds moisture more consistently, which means you won't have to water as often. Small pots can dry out in a matter of hours on a warm day, which can cause the plant to wilt.
Hanging Basket Success
For hanging baskets, cascading pendula begonias are the stars of the show. Because hanging baskets are exposed to the air on all sides, they dry out very quickly. Check them daily. If the basket feels light when you lift it from the bottom, it needs a deep watering.
What to do next:
- Group containers together to create a high-humidity microclimate.
- Rotate your pots every week so the plant grows evenly on all sides.
- Fertilize container plants every two weeks to replace nutrients that wash out during watering.
Overwintering and Storage
In most parts of the United States, begonias are treated as annuals because they cannot survive the winter outdoors. However, you can easily save the tubers to plant again next spring. This is a cost-effective way to enjoy your favorite colors year after year.
When to Lift Tubers
Wait until the foliage begins to yellow or until the first light frost hits. A light frost will blacken the leaves but won't hurt the tuber underground. Once this happens, it is time to "lift" the tubers.
- Dig: Carefully dig up the tubers, being sure not to nick or bruise them.
- Clean: Gently shake off the excess soil and trim the stems back to about an inch above the tuber.
- Cure: Place the tubers in a warm, dry, shaded spot for about a week. This "curing" process allows the outer skin to toughen up, which prevents rot during storage.
Storing for Winter
Once cured, store your begonia tubers in a cool, dark, and dry place. A basement or a cool closet that stays between 40°F and 50°F is ideal.
- Place them in a paper bag or a box filled with peat moss, sawdust, or vermiculite.
- Avoid plastic bags, as they trap moisture and cause rot.
- Check on them once a month during the winter. If a tuber looks shriveled, you can give it a very light misting of water. If one looks soft or moldy, remove it immediately so it doesn't spread to the others.
Key Takeaway: Storing begonia tubers is simple: dig them up after the first frost, let them dry for a week, and keep them in a cool, dark box of peat moss until spring.
Troubleshooting Common Issues
Even though begonias are generally healthy, you might run into a few common hurdles. Most issues are easily fixed by adjusting your watering or light.
Why Are the Leaves Dropping?
If your begonia suddenly drops its leaves or buds, it is usually a sign of stress. The most common cause is a dramatic change in temperature or moisture. If the soil has been allowed to get bone-dry and then is suddenly soaked, the plant may drop buds in protest. Keeping your watering schedule consistent is the best way to prevent this.
Dealing with Powdery Mildew
Powdery mildew looks like a light dusting of white flour on the leaves. It usually happens when the air is stagnant and humid. To prevent this, make sure your plants have enough space for air to circulate between them. If you see mildew, you can treat it with a mild fungicide or a mixture of water and neem oil, following the product label instructions.
Slugs and Snails
Because begonias grow in shady, moist spots, they can occasionally attract slugs or snails. These pests chew ragged holes in the leaves. You can manage them by hand-picking them off in the evening or by using a pet-safe slug bait around the base of the plants.
Simple Propagation
If you find a variety you absolutely love, you can easily make more plants through propagation. This is a fun and rewarding way to expand your garden.
Stem Cuttings
This is the easiest method. In mid-summer, snip off a healthy 4-inch stem that has a few leaves but no flowers. Remove the bottom leaves and place the stem in a glass of water or a small pot of moist potting soil. In a few weeks, roots will form. If using water, move the cutting into soil once the roots are about an inch long.
Tuber Division
Large, older tubers can sometimes be divided. In the spring, when the tuber begins to show small pink "eyes" (buds), you can cut the tuber into sections. Each section must have at least one healthy bud. Let the cut pieces dry for a day to callous over before planting them. This is exactly how potatoes are planted!
Conclusion
Growing begonias is one of the easiest ways to bring high-impact color to the shaded areas of your home and garden. By choosing the right location, providing well-drained soil, and maintaining consistent moisture, you can enjoy these tropical treasures all summer long. At Longfield Gardens, we take pride in providing high-quality tubers that are ready to perform in your yard. Remember that gardening is a journey of discovery, and begonias are some of the most forgiving and beautiful companions you can have along the way.
- Start your tubers indoors for a longer season of color.
- Plant with the indented side up and don't bury them too deep.
- Water when the top inch of soil feels dry.
- Store your tubers in a cool, dry place over the winter to enjoy them again next year.
The secret to spectacular begonias is simple: dappled shade, airy soil, and a little bit of patience. These plants aren't just flowers; they are an invitation to slow down and enjoy the beauty of your garden.
FAQ
Can begonias grow in full sun?
Most tuberous begonias prefer partial shade and may scorch in direct afternoon sun. However, wax begonias and certain newer hybrids are bred to handle more sunlight if they are kept consistently moist. Always check the specific variety's label, but when in doubt, dappled shade is the safest choice.
How often should I fertilize my begonias?
Begonias are heavy feeders that benefit from regular nutrients. We suggest using a water-soluble fertilizer every two weeks during the growing season. This supports the plant's energy needs for producing large, frequent blooms from summer through fall.
Why aren't my begonia tubers sprouting?
The most common reasons for slow sprouting are cold temperatures and planting too deep. Begonia tubers need warmth (at least 60°F) to wake up. Ensure they are covered by no more than an inch of soil and kept in a warm spot with indirect light to encourage growth.
Do I need to dig up my begonias every year?
If you live in USDA zones 9 through 11, begonias can often stay in the ground year-round. In colder zones (3 through 8), the tubers will freeze and rot if left outside. In these areas, you must dig them up and store them indoors if you wish to grow the same plants the following year.