Begonias, belonging to the genus Begonia, are a remarkably diverse group of plants prized for their stunning foliage and flowers. Their care requirements differ significantly based on their root structure and growth habit, which are key botanical differentiators. The Rex, Tuberous, and Cane begonias represent three distinct horticultural classes, each with unique physiological needs stemming from their morphology. Understanding these differences is essential for providing the correct cultural conditions.
Rex begonias are primarily celebrated for their spectacular, textured, and vividly colored leaves rather than their flowers. Botanically, they are rhizomatous begonias, meaning they grow from a modified, horizontal stem called a rhizome that sits at or just below the soil surface. This rhizome stores water and nutrients. Their foliage is highly specialized, with a complex surface of hairs, bumps, and vibrant pigments that maximize light absorption in the dappled shade of their native habitats. Care focuses on maintaining this foliage. They demand consistently moist but extremely well-draining soil to prevent rhizome rot. High humidity is crucial to prevent leaf scorch and desiccation, but water on the leaves can cause spotting and mildew. They thrive in bright, indirect light; direct sun will scorch their delicate leaves.
Tuberous begonias are grown for their breathtakingly large and rose-like flowers. Their defining botanical feature is their tuber, a swollen underground storage organ that is a modified stem. This tuber allows the plant to survive a dormant period. Their care is consequently cyclical. During the active growing and blooming season, they require consistently moist soil, high humidity, and regular feeding to support their massive floral display. They prefer bright, dappled light and protection from strong winds that can damage their often-heavy blooms. As daylight shortens in autumn, the plant will naturally begin to die back. At this point, watering must cease entirely. The tuber must be dug up and stored dormant in a cool, dry, and frost-free place through winter, to be replanted the following spring.
Cane begonias are characterized by their upright, segmented stems that resemble bamboo canes, with prominent nodes and internodes. These woody, jointed canes support large, often angel-wing-shaped leaves and drooping clusters of flowers. Their growth habit is more shrub-like and they do not have a dormant period like tuberous begonias. They are vigorous growers and require strong, indirect light to full morning sun to maintain compact growth and prevent legginess. While they prefer moist soil, they are generally more tolerant of slight drying between waterings compared to Rex types. Their care is less about seasonal cycles and more about consistent year-round maintenance: regular watering, feeding during growth periods, and pruning to control size and encourage branching. They benefit from higher humidity but are often more adaptable than Rex begonias.
