The Begonia semperflorens, commonly known as the Wax Begonia, is a popular bedding plant prized for its glossy foliage and continuous blooms from spring until the first frost. Its widespread use as a seasonal filler often leads gardeners to wonder about its actual life cycle: whether it must be replanted every year or if it will return on its own.
Botanical Status vs. Garden Use
Wax Begonias are botanically classified as tender perennials, meaning they possess the genetic ability to live for more than two years. They are fibrous-rooted plants. This perennial nature is evident in their native habitats of Central and South America, where they thrive in consistently warm, humid conditions.
They are overwhelmingly treated as annuals in most of the world due to frost intolerance. Wax Begonias will not survive freezing temperatures and succumb to the first hard frost of the season. They only survive year-round outdoors in the mildest climates, specifically USDA Hardiness Zones 9, 10, and 11. Gardeners in cooler regions utilize them as annuals for summer color before they die back in the fall.
Seasonal Care and Optimal Growth
Providing the right conditions ensures a dense, colorful display. Wax Begonias flourish in well-draining, moderately fertile soil, which can be improved with compost before planting. Although often considered shade plants, they tolerate a wide range of light, performing best in partial shade to full sun depending on the local climate.
Bronze-leaved varieties typically handle more direct sun exposure than those with green leaves. It is important to keep the soil consistently moist, especially for plants in sunnier locations, but avoid waterlogging the soil to prevent root rot. An application of a balanced, water-soluble fertilizer once a month during the active growing season will support continuous blooming.
Overwintering for Year-to-Year Survival
For gardeners outside of frost-free zones, Wax Begonias can be treated as houseplants to preserve them through the winter. This involves bringing them indoors before the first expected frost. Before transplanting, inspect the foliage carefully for pests, such as mealybugs or thrips, which could infest other indoor plants.
If planted in the ground, they should be carefully dug up and potted into containers using a high-quality, well-draining potting mix. The plants can be lightly pruned by cutting back leggy growth and removing any spent flowers or damaged foliage. This preparation helps the plant transition indoors.
There are two primary methods for overwintering Wax Begonias indoors. The first is to keep them actively growing by placing them near a bright, south-facing window or under supplemental light. In this scenario, they will continue to bloom, requiring regular watering when the top inch of soil is dry and occasional, reduced-strength fertilization. The second option is to allow them to go semi-dormant by placing them in a cooler, less bright area, such as a cool basement or garage, where temperatures remain above 50°F (10°C). For semi-dormant plants, watering should be drastically reduced, only providing moisture when the soil is completely dry to prevent the fibrous roots from shriveling.