Growing Tuberous Begonias (Begonia tuberosa): A Complete Guide to Planting, Care, and Maintenance

Tuberous begonias (Begonia tuberosa) are prized for their stunning, large blooms and vibrant colors that brighten up any garden or container. Known for their unique, decorative flowers, these begonias come in a variety of shapes and colors, ranging from soft pastels to vivid shades. Tuberous begonias are excellent for adding a touch of elegance to flower beds, borders, and patios. This comprehensive guide will teach you how to plant, grow, and care for tuberous begonias to ensure they thrive and produce breathtaking blooms all summer long.

Why Grow Tuberous Begonias?

Tuberous begonias are a popular choice for gardeners and flower enthusiasts alike due to their beautiful flowers and versatile growing options. Here’s why you should consider adding Begonia tuberosa to your garden:

Stunning Blooms: Tuberous begonias produce large, showy flowers that can be single or double, providing a spectacular display from late spring to frost.
Diverse Color Range: Available in a wide array of colors, including red, pink, yellow, white, and orange, they offer versatility in garden design and combinations.
Shade Tolerance: Tuberous begonias thrive in partial to full shade, making them an excellent choice for shaded garden spots or areas with filtered sunlight.
Container Friendly: These begonias are perfect for container gardening, allowing you to create vibrant displays on patios, balconies, or entrances.
Long Blooming Period: With proper care, tuberous begonias can bloom continuously from late spring through the fall, adding color and life to your garden.

Let’s explore how to successfully grow tuberous begonias and enjoy their stunning blooms throughout the summer season.

Best Varieties of Tuberous Begonias

There are many varieties of tuberous begonias, each offering unique flower shapes, colors, and sizes. Here are some popular varieties to consider for your garden:

1. Begonia tuberosa ‘Nonstop’

Description: This popular series produces an abundance of large, double blooms in various colors, including red, pink, and white. It’s known for its prolific flowering and strong stems.
Ideal for: Container gardens, borders, and mixed flower beds.

2. Begonia tuberosa ‘Picotee’

Description: Characterized by its striking bi-colored flowers with edges that contrast sharply with the petals’ main color, ‘Picotee’ varieties come in shades like red and white or pink and white.
Ideal for: Adding interest to borders and containers.

3. Begonia tuberosa ‘Giant’

Description: Known for its enormous blooms that can reach up to 6 inches across, this variety is perfect for creating a dramatic impact in any garden.
Ideal for: Focal points, large containers, and mixed plantings.

4. Begonia tuberosa ‘Hollywood’

Description: Featuring large, upright blooms with a beautiful trailing habit, this variety is perfect for hanging baskets or elevated containers.
Ideal for: Creating cascading displays on patios or balconies.

5. Begonia tuberosa ‘Double Flowered’

Description: This variety boasts lush, full double flowers in a range of colors, providing a classic look for any garden.
Ideal for: Borders, cutting gardens, and mass plantings.

By selecting a mix of tuberous begonia varieties, you can create a vibrant and dynamic display that will bloom throughout the summer.

How to Plant Tuberous Begonias

1. When to Plant Tuberous Begonias

Tuberous begonias should be planted in the spring, typically after the last frost date in your area. This allows the tubers to establish roots and grow without the risk of frost damage.

2. Choosing the Right Location

Tuberous begonias prefer partial shade to full shade and thrive in well-draining, rich, organic soil. They can tolerate some direct sunlight but benefit from protection during the hottest parts of the day. Ideal locations include areas with dappled sunlight or morning sun and afternoon shade.

3. Preparing the Soil

Tuberous begonias grow best in slightly acidic to neutral soil (pH 6.0-7.0). Before planting, loosen the soil to a depth of 8 to 10 inches and mix in plenty of compost or well-rotted manure to provide essential nutrients and improve drainage.

4. Planting Depth and Spacing

Depth: Plant tuberous begonia tubers about 2 to 4 inches deep, with the concave side facing up.
Spacing: Space the tubers 12 to 18 inches apart to allow for proper growth and air circulation. This will help prevent fungal diseases.

5. How to Plant Tuberous Begonias

Dig the Holes: Use a trowel to dig holes or a trench for planting.
Position the Tubers: Place the tubers in the holes with the concave side facing up.
Cover with Soil: Gently cover the tubers with soil, pressing down lightly to remove air pockets.
Water: Water the planting area thoroughly after planting to help the tubers settle in.

6. Mulching (Optional)

Applying a layer of mulch can help retain moisture in the soil and suppress weeds, especially during the initial growing period.

Caring for Tuberous Begonias Throughout the Growing Season

1. Watering

Tuberous begonias require regular watering, especially during dry spells. Keep the soil consistently moist but not soggy, as overwatering can lead to tuber rot. Water the plants at the base rather than from above to prevent fungal diseases.

2. Fertilizing

Fertilize tuberous begonias every 4-6 weeks during the growing season with a balanced, water-soluble fertilizer (such as 20-20-20). This will provide the necessary nutrients for healthy growth and abundant blooms. Reduce fertilization in late summer as the plants prepare for dormancy.

3. Deadheading and Maintenance

Remove spent flowers (deadheading) regularly to encourage more blooms and maintain the plant’s appearance. As the growing season progresses and foliage starts to yellow in late summer, you can trim back the leaves to tidy up the garden.

4. Preparing for Dormancy

At the end of the growing season, after the first frost, it’s essential to prepare tuberous begonias for dormancy:

Stop Watering: Allow the foliage to die back naturally, and stop watering the plants as they enter dormancy.
Lift Tubers: Once the foliage has died back completely, carefully dig up the tubers using a spade or garden fork.
Cure Tubers: Allow the tubers to dry in a cool, dark, and dry place for about a week.
Store Tubers: Store the cured tubers in a breathable container (such as a paper bag or box) in a cool, dry location until spring.

Growing Tuberous Begonias in Containers

Tuberous begonias are particularly well-suited for container gardening, allowing you to showcase their beauty on patios, balconies, or in garden beds.

Steps for Growing Tuberous Begonias in Pots:

Choose the Right Container: Use a pot that is at least 10 to 12 inches deep with drainage holes to prevent waterlogging.
Planting Depth: Plant the tubers 2 to 4 inches deep, with the concave side facing up.
Soil: Use a high-quality potting mix that is well-draining and rich in organic matter.
Watering: Water the container regularly to keep the soil moist but not soggy. Containers dry out faster than garden beds, so check the moisture level frequently.

Common Problems When Growing Tuberous Begonias

1. Tuberous Begonias Not Blooming

Cause: This may be due to inadequate light, insufficient fertilization, or overwatering.
Solution: Ensure the plants receive enough filtered sunlight, provide regular fertilization, and avoid overwatering.

2. Yellowing Leaves

Cause: Yellowing leaves may indicate overwatering or poor drainage.
Solution: Ensure the soil is well-draining, and reduce watering if necessary.

3. Pests and Diseases

Tuberous begonias can be susceptible to pests and diseases, including:

Powdery Mildew: A fungal disease that appears as a white powdery coating on leaves. Improve air circulation and avoid overhead watering to reduce humidity.
Aphids: These small pests can suck sap from the plants. Control them with insecticidal soap or neem oil.

Final Thoughts

Tuberous begonias (Begonia tuberosa) are a stunning and versatile addition to any garden, providing vibrant blooms that can last all summer long. With their easy care and resilience, they are perfect for both beginner and experienced gardeners. Whether you’re planting them in borders, containers, or as part of a mixed planting, tuberous begonias will bring beauty and elegance to your outdoor space.

Find more spring bulbs to plant in the garden and allotment here