The rieger begonia is a species of flowering shrubs, within the larger genus known commonly as begonia, that blooms perennially. This plant can produce a large, showy flower that resembles the rose in shape and appearance, and is available in a wide variety of hybrid colors. It prefers well drained soil with moderate shade and a temperate climate.
Many types of commonly available begonias are considered annual bloomers. These plants prefer warm temperatures and do not survive freezing conditions well. Unlike its more common counterparts, however, the rieger variety can bloom multiple times throughout the year, and is not limited to a spring or summer show of blooms. The frequency and hardiness of these blooming sessions is often dependent on the location of the plant, whether in a shady area of the garden, or potted in an indoor container.
When flowering, the rieger begonia can resemble a miniature rose bush. Multiple petals spring outward in a layered pattern from a central stalk, circled around a small cluster of tinier petals. The color of the bloom is determined by the variety, and ranges in shades from red to pink, peach, orange, and yellow. Rare hybrids have been bred to provide a multicolored bloom. Most commonly seen are the peach variety with petals rimmed in orange, and those with light pink blooms which contain a subtle hint of dark pink blush at the heart of each individual petal.
Common begonias are often recognizable for their variegated leaf patterns. Standard red and pink blooming varieties typically sit amidst a spray of green leaves ribbed with red or pink veins. The rieger differs from this pattern, however, by producing dark green leaves that are somewhat waxy in appearance.
The rieger begonia is considered tuberous in nature, which is unique among the genus of begonias. As a result, this particular type of begonia must be treated with more temperate care than other species within the genus, which can withstand extreme temperature changes and varying soil types. The tubers prefer a constant climate between 65° and 75° Fahrenheit (between 18° and 23° Celsius). High heat and freezing temperatures can kill this plant quickly and prevent it from returning to bloom during following seasons.
The soil in which the rieger begonia is planted should be moist and well drained. Overwatering or drying out can be as harmful to this type of shrub as extreme temperature variations. It should be placed in a shady portion of the garden which receives approximately four hours of sunlight per day. Under optimum growing conditions, this flowering bush can reach a height and width of approximately 18 inches (45 centimeters).