Begonia tuberhybrida aka Begonia Tuberosa Hybrids

Tuberous begonias typically reach 30-60 cm (12-24 inches) in both height and spread. The stems are fleshy and sturdy enough to support the heavy blooms. Growth is moderate, with tubers started in February blooming by June. For the largest flowers, thin stems to 2-3 per small tuber or 3-6 per large tuber when shoots reach 7-8 cm tall.

Tuberous begonias produce spectacular blooms from July through September in colors including white, yellow, orange, pink, red, and bicolors. Flowers can reach up to 15 cm (6 inches) across and come in single, double, ruffled, or frilled forms resembling roses, camellias, or carnations. The plants are monoecious, producing both male (showier, often double) and female flowers in clusters of three.

Tuberous begonias thrive in temperatures between 15-24°C (60-75°F) and prefer cool summers over hot, humid conditions. Start tubers at around 21°C (70°F). These hybrids were bred from high-altitude Andean species, so they struggle in extreme heat. Protect from frost—lift tubers before the first frost and store at 4-10°C (40-50°F) over winter.

Tuberous begonias can be propagated through tuber division, stem cuttings, or seed. Stem cuttings (7-8 cm) taken when shoots are young can be rooted in sand at 15-18°C over 5 weeks. Seeds require constant 21°C and 10-21 days to germinate.

There are 13 recognized groups of tuberous begonias classified by flower form. Popular types include the Non-stop Series (seed-grown, continuous bloomers), Pendula/Cascade types (trailing habit for hanging baskets), Picotee varieties (flowers with contrasting colored edges), Camellia-flowered (large double blooms), and Multiflora types (compact plants with many smaller flowers). The Non-stop Joy series offers a semi-trailing habit ideal for containers.

Tuberous begonias can be grown outdoors in USDA zones 9-11 year-round, or as summer plants in colder zones. Plant outdoors after all frost danger has passed (late May/early June in northern climates). Choose a sheltered spot with dappled shade, good air circulation, and protection from strong winds. In zones 8 and below, lift tubers before the first frost and store indoors over winter.

Deadhead spent flowers weekly during the blooming season to extend flowering and prevent seed formation. Unlike most begonias, tuberous begonias benefit from regular deadheading. Pinch stem tips every 2-4 weeks to encourage bushier growth. Use clean, sharp scissors and cut just above a leaf node. Avoid heavy pruning all at once, which can stress the plant. In fall, allow foliage to yellow naturally before cutting back for winter storage.

Repot tuberous begonias in early spring before active growth begins, typically every 1-2 years or when roots emerge from drainage holes. Choose a pot only 2-5 cm larger than the current one—these plants prefer a snug fit. Use well-draining potting mix with peat or perlite. Position the tuber with the concave side up, barely covered with soil. After repotting, water sparingly and keep out of direct sunlight until established.

Yellow leaves typically indicate overwatering—the most common care mistake with tuberous begonias. Check that soil isn't waterlogged and that the pot has good drainage. Other causes include nitrogen deficiency (older leaves yellow first), insufficient light, pest infestations (check for mealybugs or aphids), or natural dormancy in fall. If yellowing occurs in late summer/fall, it signals the plant is preparing for winter dormancy—reduce watering and allow natural die-back.

Brown leaf edges or tips usually indicate low humidity or underwatering—let soil dry only to 50-75% before watering again. Brown spots may indicate sunburn (move to shadier location) or fungal leaf spot diseases. Crispy brown patches often result from dry air or proximity to heating/cooling vents. Avoid misting foliage as this promotes powdery mildew; instead, use a pebble tray or humidifier to increase ambient humidity.

Common pests include mealybugs, aphids, whiteflies, slugs, and snails. Fungal diseases are the main concern: powdery mildew (white powder on leaves), botrytis/gray mold (soft brown rot on flowers and stems), and Pythium root rot (from overwatering). Prevent problems with good air circulation, proper spacing, and avoiding wet foliage. Remove infected plant material promptly and treat with appropriate fungicides if needed. A baking soda spray (2 tbsp per gallon water) can help control powdery mildew.

In spring, start tubers indoors 2.5-3 months before the last frost at around 18-21°C. Move outdoors after frost danger passes. During summer, maintain consistent moisture, fertilize regularly with balanced fertilizer, and deadhead spent blooms. In late summer, reduce watering and stop fertilizing. Before the first fall frost, dig tubers, cut stems to 12 cm, and cure at room temperature. Store dried tubers in peat or vermiculite at 4-10°C in a dark location, checking periodically for rot.