Frequently Asked Questions

The genus Begonia currently comprises over 2,000 recognised species, making it one of the largest genera of flowering plants. New species continue to be described through ongoing botanical surveys, particularly in tropical regions of Southeast Asia and Central America.

Begonias are native to moist subtropical and tropical regions worldwide, with the greatest species diversity found in South America, Central America, and Southeast Asia. They typically inhabit forest understory environments, rocky outcrops, and cloud forests at various elevations.

Begonias are botanically perennial, though in temperate climates they are often grown as annuals because most species cannot survive frost. Tuberous varieties can be overwintered indoors by lifting and storing their tubers, while fibrous and rhizomatous types can be maintained as houseplants year-round.

Tuberous begonias grow from underground tubers and produce large, showy flowers. They enter dormancy in autumn and require a rest period. Fibrous-rooted begonias (including wax begonias) grow from a standard root system, flower continuously, and do not have a dormancy period, though they are typically less cold-hardy.

Allow the top 2–3 centimetres of soil to dry before watering again. Frequency depends on temperature, humidity, and pot size — typically every 4–7 days during active growth, less frequently in winter. Overwatering is the most common cause of begonia failure, leading to root rot and stem collapse.

While begonias generally prefer 50–70% humidity, wax begonias and some cane-stemmed varieties adapt reasonably well to average indoor humidity levels (40–50%). Rex begonias and many rhizomatous species are more sensitive and may develop crisp leaf edges in low-humidity environments. Grouping plants together or using humidity trays can help.

Misting is generally not recommended for begonias, as water droplets on leaves can promote powdery mildew and bacterial leaf spot. Instead, increase ambient humidity through humidity trays (pebble trays with water), grouping plants together, or using a room humidifier. Good air circulation is essential.

Most begonias thrive in bright, indirect light. Direct sunlight can scorch leaves, particularly in rex and rhizomatous varieties. Wax begonias are more sun-tolerant. East-facing windows provide ideal conditions for most indoor specimens. Provide 12–14 hours of bright light daily for optimal flowering.

The optimal range is 16–24°C (60–75°F). Most species are sensitive to cold and should be protected when temperatures drop below 10°C (50°F). Avoid placing plants near draughty windows, air conditioning vents, or heating sources, as sudden temperature fluctuations can cause leaf drop.

Most begonias cannot survive frost. The notable exception is Begonia grandis, which is hardy to approximately -15°C (USDA Zone 6) and will die back to the ground in winter before re-emerging in late spring. Tuberous varieties should be lifted in autumn, dried, and stored in cool, frost-free conditions until spring replanting.

Methods vary by type: stem cuttings work well for cane-stemmed and fibrous varieties; leaf cuttings or leaf wedges are effective for rex and rhizomatous types; tuberous begonias can be propagated by dividing tubers in spring (ensuring each division has at least one growth eye); and all types can be grown from seed, though this requires patience and controlled conditions.

Yes, rex begonias propagate readily from leaf cuttings. The wedge method involves cutting a mature leaf into wedge-shaped sections, each containing a major vein, and placing them on moist growing medium. New plantlets typically emerge from the vein intersections within 4–8 weeks. Maintain high humidity and warmth (21–24°C) during this period.

Mealybugs, spider mites, and thrips are the most frequently encountered pests. Mealybugs appear as white cottony masses on stems and leaf axils. Spider mites cause stippled, yellowing foliage and fine webbing. Thrips create silvery streaks on leaves. Treat infestations promptly with insecticidal soap or neem oil.

Powdery mildew thrives in conditions of poor air circulation, moderate temperatures, and high humidity. Prevention strategies include spacing plants adequately, avoiding overhead watering, ensuring good ventilation, and removing affected leaves promptly. Fungicidal sprays containing potassium bicarbonate can be effective for treatment.

Brown leaf edges (leaf scorch) most commonly indicate low humidity, inconsistent watering, or excessive fertiliser concentration. Less frequently, it may result from fluoride sensitivity (use filtered or rainwater) or root damage from overwatering. Assess environmental conditions systematically to identify the underlying cause.