Mounding begonias are so named for their growing habit. These annual flowers tend to grow in neat, upright mounds, according to Ohio State University. Also called "wax begonias" for the waxy appearance of their leaves and blooms, these flowers grow well in full shade and bloom in shades of pink, creamy white and red.
Mounding begonias have fibrous roots, unlike tuberous or rhizomatous begonias. Native to Brazil, these tropical flowers are the most popular with home gardeners of all the begonia species, according to the University of Florida. Mounding begonias are extremely hardy, prolific blooms. In addition, many hybrids have been bred to grow well in full sunlight, unlike the true species (Begonia semperflorens) which only grows well in shade.
Begonia semperlorens grow in a compact, low mound. Dwarf cultivars grow to a maximum height of 8 inches, according to the Missouri Botanical Garden, while standard varieties reach 12 inches in height. The stems and leaves are thick and fleshy and range in color from bright green to bronze. The flowers have single or double rows of petals and are solid or bi-colored.
Mounding begonias are tender perennials. They cannot survive freezing temperatures and are often grown as annuals or as container plants. These flowers will only survive outdoors year-round in U.S. Department of Agriculture (USDA) plant hardiness zones 10 and 11, according to the Missouri Botanical Garden.
Begonias in general are hardy plants, and this species is no exception. They will adapt to almost any type of soil and will grow even in poor soils. Mounding begonias perform best, however, if provided with moist, loamy soil rich in organic matter. Sun tolerance varies depending on the cultivar. All are tolerant of heat, but some are not tolerant of direct sunlight.
Slugs and snails like to munch on these flowers, but sprinkling bait around the planting site will prevent these pests from munching on the blooms. Mounding begonias do not suffer from any serious insect pest problems, but can suffer from minor fungal diseases if the soil or foliage is consistently very wet.